Actual Test 640-802

Front 1

Both switches and hubs are being utilized within the Certkiller network. Which of
the following is true regarding the use of switches and hubs for network connectivity
in this network?
A. Switches take less time to process frames than hubs take
B. Hubs can filter frames
C. Switches do not forward broadcasts
D. Switches increase the number of collision domains in the network
E. Using hubs can increase the amount of bandwidth available to hosts
F. None of the above

Back 1

Answer: D
Explanation:
The biggest benefit of using switches instead of hubs in your internetwork is that each
switch port is actually its own collision domain. (Conversely, a hub creates one large
collision domain.) But even armed with a switch, you still can't break up broadcast
domains. Neither switches nor bridges will do that. They'll typically simply forward all
broadcasts instead. Switch creates the collision domain per port, so we can say switch
increase the number of collision domains.

Front 2

Which one of the following characteristics is true regarding the use of hubs and
switches?
A. Hubs can have their ports be configured with VLANs
B. Using hubs is costly with regard to bandwidth availability.
C. Switches can not forward broadcasts.
D. Switches are more efficient than hubs in processing frames.
E. Switches increase the number of collision domains in the network.

Back 2

Answer: E
Explanation: Switches increases the number of collisions domains in the network.
Switches that are configured with VLANs will reduce the size of the collision
domains by increasing the number of collision domains in a network, but making
them smaller than that of one big, flat network.

Hint 2

Incorrect Answers:
A. Switches are capable of VLAN configurations, but hubs are not.
B. Hubs are generally the least costly method possible to connect multiple devices
together in a network.
C. Switches forward broadcasts and multicasts, by default, to all ports within the same
VLAN. Only routers block all broadcast traffic by default.
D. Switches and hubs can be equally efficient in processing frames, in theory. In practice,
switches are generally more efficient as they usually have more CPU and memory
allocated to them, and are generally much more expensive than a simple hub.

Front 3

When comparing and contrasting the similarities and differences between bridges
and switches, which of the following are valid statements? Choose all the valid
answer choices)
A. Bridges are faster than switches because they have fewer ports.
B. A switch is a multiport bridge,
C. Bridges and switches learn MAC addresses by examining the source MAC address of
each frame received.
D. A bridge will forward a broadcast but a switch will not.
E. Bridges and switches increase the size of a collision domain.
F. None of the above statements are true.

Back 3

Answer: B, C
Explanation:
Both bridges and switches build the bridge table by listening to incoming frames and
examining the source MAC address in the frame.
Switches are multiport bridges that allow you to create multiple broadcast domains. Each
broadcast domain is like a distinct virtual bridge within a switch.

Hint 3

Incorrect Answers:
A. Switches are generally faster than bridges. Bridges also do not necessarily have fewer
ports than switches.
D. Both bridges and switches will forward broadcast and multicast traffic, assuming that
the traffic remains in the same VLAN.
E. The use of VLANs in a switch can decrease the size of the collision domain, by
creating additional, smaller collision domains.

Front 4

Which of the following correctly describe the various functions and virtues of a
router? (Select all valid answer choices)
A. Packet switching
B. Collision prevention on a LAN segment.
C. Packet filtering
D. Broadcast domain enlargement
E. Broadcast forwarding
F. Internetwork communication
G. None of the above

Back 4

Answer: A, C, F
Explanation:
The main function of a router is to connect different, separated networks together. In
doing so, switching packets from one network to another is a primary function, along
with providing for communication between networks. As an additional feature, routers
are capable of providing filtering on a network address and application port level, so
choice C is also correct.

Hint 4

Incorrect Answers:
B. Routers can indeed be used to segment a network separate a collision domain, since
routers do not forward LAN broadcasts and multicasts to other interfaces. However,
routers alone can not prevent all collisions from occurring on any given LAN segment.
D. Routers actually segment LANs into smaller broadcast domains.
E. Routers do not forward broadcast and multicast traffic out the additional interfaces by
default. Unless bridging or IP helpers are configured on the router, LAN broadcasts are
blocked at the router level.

Front 5

The LAN needs are expanding at the Certkiller corporate office, which is quickly
growing. You are instructed to enlarge the area covered by a single LAN segment on
the Certkiller network.
Which of the following are layer 1 devices that you can use? (Choose all that apply.)
A. A switch
B. A router
C. A network adapter card
D. A hub
E. A repeater

Back 5

Answer: D, E
Explanation:
A hub simply repeats the electrical signal and makes no attempt to interpret the electrical
signal (layer 1) as a LAN frame (Layer 2). So, a hub actually performs OSI layer 1
functions, repeating an electrical signal, whereas a switch performs OSI layer 2
functions, actually interpreting Ethernet header information, particularly addresses, to
make forwarding decisions. Hubs can be used to increase the number of stations that can be supported on a LAN.
Because the repeater does not interpret what the bits mean, but does examine and
generate electrical signals, a repeater is considered to operate at Layer 1. Repeaters can
be used to physically extend the LAN to greater distances.

Front 6

Cisco is the leader in the router market space. What basic functions do their routers
perform in a network? (Choose two)
A. The microsegmentation of broadcast domains
B. Path selection
C. Packet switching
D. Bridging between LAN segments
E. Access layer security
F. VLAN membership assignment
G. Application optimization

Back 6

Answer: B, C
Explanation:
The primary functions of a router are: Packet Switching and Path Selection. It is the
routers job to determine the best method for delivering the data, and switching that data
as quickly as possible.

Front 7

the following statements are true regarding bridges and switches in this network?
(Choose 3)
A. Switches are primarily software based while bridges are hardware based.
B. Switches usually have a higher number of ports than most bridges.
C. Bridges are frequently faster than switches.
D. Bridges define broadcast domains while switches define collision domains.
E. Both bridges and switches forward Layer 2 broadcasts.
F. Both bridges and switches make forwarding decisions based on Layer 2 addresses.

Back 7

Answer: B, E, F

Front 8

As a network administrator, you will need to decide on the appropriate network devices to use. Which of the following correctly describes the roles of devices in a
WAN? (Choose three)
A. A CSU/DSU terminates a digital local loop.
B. A router is commonly considered a DCE device.
C. A modem terminates an analog local loop.
D. A router is commonly considered a DTE device.
E. A modem terminates a digital local loop.
F. A CSU/DSU terminates an analog local loop.
G. A modem is used to terminate a T1

Back 8

Answer: A, C, D
Explanation:
Layer 2 switching is considered hardware-based bridging because it uses specialized
hardware called an application-specific integrated circuit (ASIC). ASICs can run up to
gigabit speeds with very low latency rates.
Switches usually have higher port number then bridge. Generally bridges have two ports.
Both operates on Data link layer.

Front 9

The Certkiller network administrator needs to determine what LAN devices to
install on the Certkiller network. What are two advantages of using Layer 2
Ethernet switches over hubs? (Choose two)
A. Allowing simultaneous frame transmissions
B. Increasing the size of broadcast domains
C. Increasing the maximum length of UTP cabling between devices
D. Filtering frames based on MAC addresses
E. Decreasing the number of collision domains

Back 9

Answer: A, D
Explanation:
A: A half duplex connection is where only one device can send or receive at a time. A
full duplex connection is where both devices can send and receive at the same time.
Thus, if you have a 100Mb half-duplex connection, only sending at 100Mb OR receiving
at 100Mb can happen at the same time. If you have a 100Mb full duplex connection, you
can effectively get 200Mb out of the link because you could be sending 100Mb and
receiving 100Mb at the same time.
D: Switches are capable of filtering frames based on any Layer 2 fields. For example, a
switch can be programmed to reject (not forward) all frames sourced from a particular
network. Because link layer information often includes a reference to an upper-layer protocol, switches usually can filter on this parameter. Furthermore, filters can be helpful
in dealing with unnecessary broadcast and multicast packets.

Front 10

CDP is being used throughout the Certkiller network. What are two reasons why the
Certkiller network administrator would use CDP? (Choose two)
A. To determine the status of network services on a remote device
B. To obtain the IP Address of a connected device in order to telnet to the device
C. To verify the type of cable interconnecting two devices
D. To verify Layer 2 connectivity between two devices when Layer 3 fails
E. To obtain VLAN information from directly connected switches
F. To determine the status of the routing protocols between directly connected routers
G. To support automatic network failover during outages

Back 10

Answer: B, D
Explanation:
Cisco Discovery Protocol (CDP) is a proprietary protocol designed by Cisco to help
administrators collect information about both locally attached and remote devices. By
using CDP, you can gather hardware and protocol information about neighbor devices,
which is useful info for troubleshooting and documenting the network.
You can use:
Show cdp neighbor
Show cdp neighbor details
Commands to gather the information of connected neighbors.

Front 11

CDP is running between two Certkiller devices. What information is supplied by
CDP? (Select three)
A. Device Identifiers
B. Capabilities list
C. Platform
D. Route identifier
E. Neighbor traffic data

Back 11

Answer: A, B, C
Explanation:
CDP is a Cisco proprietary protocol; to support forwarding CDP messages over an interface, that interface must support SNAP headers. Any LAN interface, HDLC, Frame Relay, and ATM all support CDP. The touter or switch can discover Layer 3 addressing details of neighboring routers (without even configuring that Layer 3 protocol) because CDP is not dependent on any particular Layer 3 protocol.

CDP discovers several useful details from the neighboring device:
1. Device Identifier - Typically the host name
2. Address list - Network and data link addresses
3. Port Identifier - Text that identifies the port, which is another name for an interface
4. Capabilities list - Information on what the device does - for instance, a router or a switch.
5. Platform - The model and OS level running in the device

Front 12

Two buildings on the London campus of a the Certkiller corporation must be
connected to use Ethernet with a bandwidth of at least 100 Mbps. Certkiller is
concerned about possible problems from voltage potential differences between the
two buildings. Which media type should be used for the connection?
A. Coaxial cable
B. Fiber optic cable
C. UTP cable
D. STP cable
E. None of the above

Back 12

Answer: B
Explanation:
Current Ethernet technology typically comes via either copper UTP or fiber cables. In
this scenario the distance between the buildings is only 55 meters so either copper or
fiber could be used, as the distance limitation for 100M UTP Ethernet is 100 meters.
However, fiber would be a better fit as it is not prone to errors that could occur due to the
voltage potential differences. Because fiber is a dielectric material, it's not susceptible to
electrical interference. FO-product vendors also claim that fiber systems make secure
communications easier. Interference immunity and lack of emissions are givens in FO
systems and in the fiber medium itself.

Front 13

You work as a network technician at Certkiller .com. Please study the exhibit
carefully. Based on the information shown above, what is needed to allow host
Certkiller 1 to ping host Certkiller 2?
A. a crossover cable connecting the switches
B. a backbone switch connecting the switches with either fiber optic or straight-through
cables
C. a straight-through cable connecting the switches
D. a CSU/DSU connected to the switches with straight-through cables
E. a router connected to the switches with straight-through cables

Back 13

Answer: E
Explanation:
Routers are Layers 3 devices used for inter-network communication. In this scenario
there are two different networks, so both switches need to connect to a router using
straight-through cables.
A straight-through cable is used to connect two different devices like, switch to router,
host to switch. Since we need to insert a router for communication between the two
switches, straight through cables will be used between the switches and the router.

Front 14

A new Certkiller office is opening, and a network device needs to be installed in the
place of the icon labeled Network Device to accommodate a leased line T1 to the
Internet. Which network device and interface configuration meets the minimum
requirements for this installation?
A. A switch with two Ethernet interfaces
B. A router with two Ethernet interfaces
C. A switch with one Ethernet and one serial interface
D. A router with one Ethernet and one serial interface
E. A router with one Ethernet and one modem interface
F. None of the above

Back 14

Answer: D
Explanation:
Only a router can terminate a leased line T1 access circuit, and only a router can connect
two different IP networks. Here, we will need a router with two interfaces, one serial
connection for the T1 and one Ethernet interface to connect to the switch on the LAN.

Front 15

which layers of the OSI Model do Wide Area Networks operate in? (Choose two)
A. Physical Layer
B. Datalink Layer
C. Network Layer
D. Session Layer
E. Transport Layer
F. Presentation Layer
G. Application Layer

Back 15

Answer: A, B
Explanation:
A WAN is a data communications network that covers a relatively broad geographic area
and that often uses transmission facilities provided by common carriers, such as
telephone companies. WAN technologies generally function at the lower two layers of
the OSI reference model: the physical layer and the data link layer as shown below.
Note: Occasionally WAN's would also be considered to operate at layer 3, but since this
question asked for only 2 choices layers 1 and 2 are better choices.

Front 16

While troubleshooting a connectivity problem on the network, you issue the ping
command from your PC command prompt, but the output shows "request times
out."
At which OSI layer is this problem associated with?
A. The data link layer
B. The application layer
C. The access layer
D. The session layer
E. The network layer

Back 16

Answer: E
Explanation:
TCP/IP includes ICMP, a protocol designed to help manage and control the operation of
a TCP/IP network. The ICMP protocol provides a wide variety of information about a
network's health and operational status. Control message is the most descriptive part of a
name. ICMP helps control and manage IP's work and therefore is considered part of
TCP/IP's network layer.

Hint 16

Reference:
CCNA Self-Study CCNA ICND exam certification Guide (Cisco Press, ISBN
1-58720-083-X) page 277.

Front 17

You download a file from an FTP site on the Internet. What is the highest layer in the
OSI model used in this FTP operation?
A. Application
B. Presentation
C. Session
D. Transport
E. Internet
F. Data Link
G. Physical

Back 17

Answer: A
Explanation:
Layer 7 is the application layer, which is the highest layer in the OSI model. This layer
describes the use of end user applications, such as opening movie files (avi, mpeg, etc)
used Microsoft Office applications, using WWW browsers, using Telnet, and using FTP.

Front 18

A host computer has been correctly configured with a static IP address, but the
default gateway is incorrectly set. Which layer of the OSI model will be first
affected by this configuration error?
A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4
E. Layer 5
F. Layer 6
E. Layer 7

Back 18

Answer: C
Explanation:
IP Addressing and IP routing resides on the OSI Network layer, which is layer 3.

Front 19

Which layer of the OSI reference model is responsible for ensuring reliable
end-to-end delivery of data?
A. Application
B. Presentation
C. Session
D. Transport
E. Network
F. Data-Link

Back 19

Answer: D
Explanation:
A key function of the transport layer is to provide connection services for the protocols
and applications that run at the levels above it. These can be categorized as either
connection-oriented services or connectionless services. Some protocol suites, such as
TCP/IP, provide both a connection-oriented and a connectionless transport layer
protocol, to suit the needs of different applications.
The transport layer is also the place in the layer stack where functions are normally
included to add features to end-to-end data transport. Where network layer protocols are
normally concerned with just "best effort" communications, where delivery is not
guaranteed. Transport layer protocols are given intelligence in the form of algorithms that
ensure that reliable and efficient communication between devices takes place. This
encompasses several related jobs, including lost transmission detection and handling, and
managing the rate at which data is sent to ensure that the receiving device is not
overwhelmed.
Transmission quality, meaning ensuring that transmissions are received as sent, is so
important that some networking references define the transport layer on the basis of
reliability and flow-control functions. However, not all transport layer protocols provide
these services. Just as a protocol suite may have a connection-oriented and a
connectionless transport layer protocol, it may also have one that provides reliability and
data management services, and one that does not. Again, this is the case with TCP/IP:
there is one main transport layer protocol; TCP, that includes reliability and flow control
features, and a second, UDP, that doesn't.

Front 20

At which OSI layer is a logical path created between two host systems named CK1
and CK2 on the Certkiller LAN?
A. Physical
B. Session
C. Data link
D. Transport
E. Network
F. Application
G. Presentation

Back 20

Answer: E
Explanation:
The Network layer (also called layer 3) manages device addressing, tracks the location of
devices on the network, and determines the best way to move data, which means that the
Network layer must transport traffic between devices that aren't locally attached. Routers
(layer 3 devices) are specified at the Network layer and provide the routing services
within an internetwork.

Front 21

Which OSI layer is associated with the following: The acknowledgement of
transmissions, sequencing, and flow control across a network?
A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 5
E. Layer 6
F. Layer 7

Back 21

Answer: C
Explanation:
The Transport layer (Layer 4) defines several functions, including the choice of
protocols. The most important Layer 4 functions are error recovery and flow control. The
transport layer may provide for retransmission, i.e., error recovery, and may use flow
control to prevent unnecessary congestion by attempting to send data at a rate that the
network can accommodate, or it might not, depending on the choice of protocols.
Multiplexing of incoming data for different flows to applications on the same host is also
performed. Reordering of the incoming data stream when packets arrive out of order is
included. Examples include: TCP, UDP, and SPX.

Front 22

Which OSI layer header contains the address of a destination host that is on another
network?
A. Application
B. Presentation
C. Session
D. Transport
E. Network
F. Data link
G. Physical

Back 22

Answer: E
Explanation:
Only network address contains this information. To transmit the packets the sender uses
network address and datalink address. But the layer 2 address represents just the address
of the next hop device on the way to the sender. It is changed on each hop. Network
address remains the same.

Front 23

Which of the following correctly describe steps in the OSI data encapsulation
process? (Choose two)
A. The presentation layer translates bits into voltages for transmission across the physical
link.
B. The transport layer divides a data stream into segments and adds reliability and flow
control information.
C. Packets are created when the network layer adds Layer 3 addresses and control
information to a segment.
D. The data link layer adds physical source and destination addresses and an FCS to the
segment.
E. Packets are created when the network layer encapsulates a frame with source and
destination host addresses and protocol-related control information.

Back 23

Answer: B, C
Explanation:
The Transport Layer:
You can think of the transport layer of the OSI model as a boundary between the upper
and lower protocols. The transport layer provides a data transport service that shields the
upper layers from transport implementation issues such as the reliability of a connection.
The transport layer provides mechanisms for:
Segmenting upper layer application
The establishment, maintenance, and orderly termination of virtual circuits
information flow control and reliability via TCP
Transport fault detection and recovery
The Network Layer:
Layer three of the OSI model is the network layer.
The network layer creates and sends packets from source network to destination
network.
it provides consistent end-to-end packet delivery service and control information
it creates and uses layer3 addresses for use in path determination and to forward
packets.

Hint 23

Incorrect Answers:
A: This correctly describes the physical layer, not the presentation layer.
D: Although the data link layer adds physical (MAC) source and destination addresses, it
adds it to a frame, not a segment.
E: Packets are encapsulated, not frames.

Front 24

When files are transferred between a host and an FTP server, the data is divided
into smaller pieces for transmission. As these pieces arrive at the destination host,
they must be reassembled to reconstruct the original file. What provides for the
reassembly of these pieces into the correct order?
A. The sequence number in the TCP header
B. The Start Frame Delimiter in the 802.3 Preamble
C. The TTL in the IP header
D. The acknowledgement number in the segment header
E. The frame check sequence in the Ethernet frame trailer

Back 24

Answer: A
Explanation:
The Transport layer can provide reliable networking via acknowledgments, sequencing,
and flow control.
Acknowledgments Delivered segments are acknowledged to the sender. If they are not
acknowledged, the sender will retransmit.
Sequencing Data segments are sequenced into their original order when they arrive at the
destination.
Flow Control Provides buffer controls that prevent packet flooding to the destination
host. Buffers store bursts of data for processing when the transmission is complete.
Layer 4 protocols include the following:
Transmission Control Protocol (TCP)
User Datagram Protocol (UDP)
Sequenced Packet Exchange (SPX)A reliable communications protocol created by
Novell NetWare

Front 25

Network equipment supporting the use of flow control mechanisms has been recently installed in the Certkiller network. What is the purpose of flow control in a
data network?
A. It ensures that data is retransmitted if an acknowledgment is not received.
B. It reassembles segments in the correct order on the destination device.
C. It provides a mechanism for the receiver to control the transmission speed.
D. It regulates the size of each datagram segment.
E. All of the above are functions of flow control

Back 25

Answer: C
Explanation:
Flow control paces the transmission of data between a sending device and a receiving
device. Flow control ensures that the receiving device can absorb the data sent to it
before the sending device sends more. When the buffers on the receiving device are full,
a message is sent to the sending device to suspend transmission until the data in the
buffers has been processed.

Hint 25

Incorrect Answers:
A. Data retransmission mechanisms are not handled by control. They are most often
handled by transport layer protocols such as TCP.
B. This describes the reassembly portion of the segmentation and reassembly (SAR)
function of network equipment.
D. The maximum transmission unit (MTU) handles the regulation of maximum frame
sizes.

Front 26

You have just installed a new web server on the Certkiller network. You are required
to ensure that the web server is accessible from the Internet. The network uses
private addressing, so an IP-to-registered address mapping is required.
To do this, you enter the following command:
Certkiller (config)# ip nat inside source static 192.168.2.1
198.18.1.254
You unsuccessfully try to ping the Internet from a PC host on the LAN. During the
troubleshooting process, you enter the "show ip nat translations" command but the
output is blank.
What is the most likely cause of the problem?
A. The keyword overload is missing from the command.
B. The NAT pool must be defined first.
C. An access list must be defined to create static NAT translations.
D. The interfaces must be configured for NAT.
E. None of the above

Back 26

Answer: D
Explanation:
In order to successfully configure a static NAT translation, the interfaces must be
configured for NAT, in addition to the global NAT command that was entered. The
router interface that lies on the inside part of the network must be defined using the "ip
nat inside" command. Similarly, the WAN interface that is being used for the Internet
connection must be defined using the "ip nat outside" command.

Hint 26

Incorrect Answers:
A. In order to make an internal server reachable from the Internet, a static one to one
NAT entry must be configured for the server. The keyword "overload" is used to
configure many to one NAT, or PAT.
B, C. This need not be done in order to create a static NAT entry. These steps are
typically done in setting up NAT so that inside LAN users can access the Internet via
NAT.

Front 27

Which protocol below uses TCP port 443 at layer 4?
A. HTML
B. HTTPS
C. TFTP
D. Telnet
E. SMTP
F. None of the above

Back 27

Answer: B
Explanation:
HTTPS is the secured version of the HTTP application, which normally uses 128 bit SSL
encryption to secure the information sent and received on a web page. An example is a
banking web site, or a trustworthy shopping web site that takes credit card information. It
is an application layer protocol which uses TCP port 443.

Hint 27

Incorrect Answers:
A. HTML is not a protocol.
C. TFTP uses UDP port 69.
D. Telnet uses TCP port 23.
E. SMTP uses TCP port 25.

Front 28

As a CCNA candidate, you will be expected to know the OSI model very well.
Which of the following are associated with the application layer (layer 7) of the OSI
model? (Choose two)
A. TCP
B. Telnet
C. FTP
D. Ping
E. IP
F. UDP

Back 28

Answer: B, C
Explanation:
The application layer is the top layer of the OSI model and is used to describe the end
user applications that can be used over a network.
Layer Name Examples
Application (layer 7) Telnet, HTTP, FTP, WWW browsers, NFS, SMTP gateways,
SNMP

Hint 28

Incorrect Answers:
A. TCP resides at layer 4.
D. ARP is a function of the data link layer, which is layer 2.
E. IP is used at layer 3 (network layer).
Reference: CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press,
ISBN 1-58720-094-5) Page 34.

Front 29

As the Certkiller network administrator, you are required to have a firm
understanding of the OSI model. Why does the data communication industry use
the layered OSI reference model? (Choose two)
A. It enables equipment from different vendors to use the same electronic components,
thus saving research and development funds
B. It encourages industry standardization by defining what functions occur at each layer
of the model
C. It divides the network communication process into smaller and simpler components;
thus aiding component development, design and troubleshooting
D. It provides a means by which changes in functionality in one layer require changes in
other layers
E. It supports the evolution of multiple competing standards and thus provides business
opportunities for equipment manufacturers

Back 29

Answer: B, C
Explanation:
The OSI (Open System Interconnection) reference model was created as a reference point
for communications devices. A layered approach is used to segment the entire
telecommunications process into a series of smaller steps.
A is correct because it encourages a level of standardization by encouraging that
functions be compared to known layers. D is also correct because it allows engineers to
focus on the development, refining, and perfection of simpler components.

Front 30

You need to describe the various types of flow control to your co-workers. Which of
the following are types of flow control that can be used in a network? (Choose three)
A. Congestion avoidance
B. Windowing
C. Cut-through
D. Buffering
E. Load Balancing
F. Fast Forward

Back 30

Answer: A, B, D

Front 31

Which of the protocols below use TCP at the transport layer? (Select four)
A. TFTP
B. SMTP
C. SNMP
D. FTP
E. HTTP
F. HTTPS

Back 31

Answer: B, D, E, F
Explanation:
SMTP (Simple Mail Transfer Profile for email), FTP (File Transfer Protocol), and
HTTP/HTTPS (Hyper Text Transfer Protocol for internet) all use TCP because of the
reliable delivery mechanism. SMTP uses TCP port 25, FTP uses TCP ports 20 and 21,
HTTP uses TCP port 80, and HTTPS uses TCP port 443.

Hint 31

Incorrect Answers:
A, C: SNMP and TFTP use UDP as the transport mechanism. Generally speaking,
protocols that use the keywords "trivial" or "simple" uses UDP, since connectionless,
best effort delivery mechanism usually suffice.
Reference: CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press,
ISBN 1-58720-094-5) Page 163.

Front 32

Which fields are included in the TCP header? (Choose three).
A. Source Port
B. Acknowledgement Number
C. Request Number
D. Destination Address
E. Window
F. Data

Back 32

Answer: A, B, E
Explanation:
TCP header:
Source Port: 16 bits.
Destination Port: 16 bits.
Sequence Number: 32 bits.
The sequence number of the first data byte in this segment. If the SYN bit is set, the
sequence number is the initial sequence number and the first data byte is initial sequence
number + 1.
Acknowledgment Number: 32 bits.
If the ACK bit is set, this field contains the value of the next sequence number the sender
of the segment is expecting to receive. Once a connection is established this is always
sent.
Data Offset: 4 bits.
The number of 32-bit words in the TCP header. This indicates where the data begins. The
length of the TCP header is always a multiple of 32 bits.
Reserved: 3 bits.
Must be cleared to zero.
ECN, Explicit Congestion Notification: 3 bits.
Added in RFC 3168.
Control Bits: 6 bits.
Window: 16 bits, unsigned.
The number of data bytes beginning with the one indicated in the acknowledgment field
which the sender of this segment is willing to accept.
Checksum: 16 bits.
This is computed as the 16-bit one's complement of the one's complement sum of a
pseudo header of information from the IP header, the TCP header, and the data, padded
as needed with zero bytes at the end to make a multiple of two bytes.
Urgent Pointer: 16 bits, unsigned.
If the URG bit is set, this field points to the sequence number of the last byte in a
sequence of urgent data.
Options: 0 to 44 bytes.
Options occupy space at the end of the TCP header. All options are included in the
checksum. An option may begin on any byte boundary. The TCP header must be padded
with zeros to make the header length a multiple of 32 bits.
Data: Variable length.

Front 33

Acknowledgements, sequencing, and flow control are functions that are handled by
which layer of the OSI model?

A. Layer 5
B. Layer 4
C. Layer 7
D. Layer 6
E. Layer 3
F. Layer 2
G. Layer 1

Back 33

Answer: B

Front 34

A receiving host has failed to receive all of the segments that it should acknowledge.
What can the host do to improve the reliability of this communication session?
A. Start a new session using UDP
B. Obtain a new IP address from the DHCP server
C. Use a different source port for the session
D. Decrease the sequence number
E. Decrease the window size

Back 34

Answer: E
Explanation:
A TCP window the amount of outstanding (unacknowledged by the recipient) data a
sender can send on a particular connection before it gets an acknowledgment back from
the receiver that it has gotten some of it.
For example if a pair of hosts are talking over a TCP connection that has a TCP window
size of 64 KB (kilobytes), the sender can only send 64 KB of data and then it must stop
and wait for an acknowledgment from the receiver that some or all of the data has been
received. If the receiver acknowledges that all the data has been received then the sender
is free to send another 64 KB.
One way to improve the reliability of the TCP connection is to reduce the window size
that the receiver needs to receive before sending an acknowledgement. However, this will
reduce throughput as more segments and acknowledgements will need to be sent in order
to transfer the same amount of data.

Front 35

You have set up an Internet based FTP server, where people can upload and
download files. In terms of the OSI model, what is the highest layer used during the
FTP sessions.
A. Application
B. Presentation
C. Session
D. Transport
E. Internet
F. Data Link
G. Physical

Back 35

Answer: A
Explanation:
The application layer is the highest layer (layer 7) of the OSI model, and is reserved for
end user applications. Since FTP is itself an application, layer 7 is the highest layer used.

Hint 35

Incorrect Answers:
B, C, D, E, F, G. In any given FTP session, all of these layers will be used at some point
but they are incorrect because the question asked for the highest layer used by FTP.

Front 36

ICMP is often used in troubleshooting and verifying network. What statements are
true regarding ICMP packets? (Choose two)
A. They acknowledge receipt of TCP segments.
B. They guarantee datagram delivery.
C. They can provide hosts with information about network problems.
D. They are encapsulated within IP datagrams.
E. They are encapsulated within UDP datagrams.
F. They are encapsulated within TCP datagrams.

Back 36

Answer: C, D
Explanation:
ping may be used to find out whether the local machines are connected to the network or
whether a remote site is reachable. This tool is a common network tool for determining
the network connectivity which uses ICMP protocol instead of TCP/IP and UDP/IP. This
protocol is usually associated with the network management tools which provide network
information to network administrators, such as ping and traceroute (the later also uses the
UDP/IP protocol).
ICMP is quite different from the TCP/IP and UDP/IP protocols. No source and
destination ports are included in its packets. Therefore, usual packet-filtering rules for
TCP/IP and UDP/IP are not applicable. Fortunately, a special "signature" known as the
packet's Message type is included for denoting the purposes of the ICMP packet. Most
commonly used message types are namely, 0, 3, 4, 5, 8, 11, and 12 which represent echo
reply, destination unreachable, source quench, redirect, echo request, time exceeded, and
parameter problem respectively.
In the ping service, after receiving the ICMP "echo request" packet from the source
location, the destination

Hint 36

Incorrect Answers
ICMP is an IP protocol so A and E are incorrect.
ICMP doesn't guarantee datagram delivery so B is wrong as well.

Front 37

Which of the following services use TCP? (Choose three)
A. DHCP
B. SMTP
C. SNMP
D. FTP
E. HTTP
F. TFTP

Back 37

Answer: B, D, E
Explanation:
TCP (Transmission Control Protocol) is a reliable mechanism for data delivery. SMTP,
FTP and HTTP services use TCP via ports 25, 20/21, and 80, respectively.

Front 38

Which of the following are types of flow control? (Choose three)
A. Buffering
B. Cut-through
C. Windowing
D. Congestion avoidance
E. Load balancing

Back 38

Explanation:
Data transmission flow control occurs at layer 4 with the help of buffering, windowing
and congestion avoidance.

Hint 38

Reference: CCNA Cisco Certified Network Associate Study Guide, 5th Edition, Todd
Lammle, chapter 1, page 17.

Front 39

Which Layer 4 protocol is used for a Telnet connection between two Certkiller
routers?
A. IP
B. ICMP
C. DNS
D. TCP
E. UDP
F. RTP

Back 39

Answer: D
Explanation:
TCP is a reliable connection-oriented protocol. TCP uses acknowledgments, sequencing,
and flow control to ensure reliability. Telnet uses TCP port 23.

Front 40

FTP, Telnet, DNS, and SMTP are all protocols being used in the Certkiller network.
Of these, which uses both TCP and UDP ports?
A. Telnet
B. FTP
C. DNS
D. SMTP
E. None of the above

Back 40

Answer: C
Explanation:
The following port numbers for the protocols listed above are as follows:
FTP: TCP Port 20 and 21
SMTP: TCP Port 25
Telnet: TCP Port 23
DNS: both TCP and UDP Port 53

Front 41

Although TCP segments are similar to UDP segments, TCP packets contains some
additional fields. Which of the following are found in a TCP header, but not in a
UDP header? (Choose three)
A. Checksum
B. Sequence number
C. Destination port
D. Window size
E. Acknowledgment number
F. Source port

Back 41

Answer: B, D, E
Explanation:
The Figure below illustrates the fields and overall format of a TCP packet.
Twelve fields comprise a TCP packet.
TCP Packet Field Descriptions
The following descriptions summarize the TCP packet fields illustrated in Figure 30-10:
1. Source Port and Destination Port-Identifies points at which upper-layer source and
destination processes receive TCP services.
2. Sequence Number-Usually specifies the number assigned to the first byte of data in the
current message. In the connection-establishment phase, this field also can be used to
identify an initial sequence number to be used in an upcoming transmission.
3. Acknowledgment Number-Contains the sequence number of the next byte of data the
sender of the packet expects to receive.
4. Data Offset-Indicates the number of 32-bit words in the TCP header.
5. Reserved-Remains reserved for future use.
6. Flags-Carries a variety of control information, including the SYN and ACK bits used
for connection establishment, and the FIN bit used for connection termination.
7. Window-Specifies the size of the sender's receive window (that is, the buffer space
available for incoming data).
8. Checksum-Indicates whether the header was damaged in transit.
9. Urgent Pointer-Points to the first urgent data byte in the packet.
10. Options-Specifies various TCP options.
11. Data-Contains upper-layer information.
User Datagram Protocol (UDP)
The User Datagram Protocol (UDP) is a connectionless transport-layer protocol (Layer 4)
that belongs to the Internet protocol family. UDP is basically an interface between IP and
upper-layer processes. UDP protocol ports distinguish multiple applications running on a
single device from one another.
Unlike the TCP, UDP adds no reliability, flow-control, or error-recovery functions to IP.
Because of UDP's simplicity, UDP headers contain fewer bytes and consume less
network overhead than TCP.
UDP is useful in situations where the reliability mechanisms of TCP are not necessary,
such as in cases where a higher-layer protocol might provide error and flow control.
UDP is the transport protocol for several well-known application-layer protocols,
including Network File System (NFS), Simple Network Management Protocol (SNMP),
Domain Name System (DNS), and Trivial File Transfer Protocol (TFTP).
The UDP packet format contains four fields, as shown in the figure below. These include source and destination ports, length, and checksum fields.
A UDP packet consists of four fields.
Source and destination ports contain the 16-bit UDP protocol port numbers used to
demultiplex datagrams for receiving application-layer processes. A length field specifies
the length of the UDP header and data. Checksum provides an (optional) integrity check
on the UDP header and data.

Hint 41

Reference: http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/ip.htm#xtocid21

Front 42

Certkiller is installing IP phones in a new office. The phones and office computers
connect to the same device. To ensure maximum throughout for the phone data
sessions, the company needs to make sure that the phone traffic is on a different
network from that of the office computer data traffic. What is the best network
device to which to directly connect the phones and computers and what technology
should be implemented on this device? (Choose two)
A. VLAN
B. Subinterface
C. STP
D. Hub
E. Switch
F. Router
G. Wireless Access Point
H. VTP

Back 42

Answer: A, E

Front 43

The corporate head office of Certkiller has a teleconferencing system that uses VOIP
640-802
Actualtests.com - The Power of Knowing
(voice over IP) technology. This system uses UDP as the transport for the data
transmissions. If these UDP datagrams arrive at their destination out of sequence,
what will happen?
A. UDP will send an ICMP Information Request to the source host.
B. UDP will pass the information in the datagrams up to the next OSI layer in the order
that they arrive.
C. UDP will drop the datagrams.
D. UDP will use the sequence numbers in the datagram headers to reassemble the data in
the correct order.
E. UDP will not acknowledge the datagrams and wait for a retransmission of the
datagrams.

Back 43

Answer: B
Explanation:
VOIP systems utilize UDP because it is faster and uses less overhead. In addition, the
reliable transport mechanism used in TCP is useless to VOIP because if a packet gets
dropped and needs to be resent, it will be already too late.
UDP provides a service for applications to exchange messages. Unlike TCP, UDP is
connectionless and provides no reliability, no windowing, and no reordering of the
received data. However, UDP provides some functions of TCP , such as data transfer,
segmentation, and multiplexing using port numbers, and it does so with fewer bytes of
overhead and with less processing required. UDP data transfer differs from TCP data
transfer in that no reordering or recovery is accomplished. Applications that use UDP are
tolerant of lost data, or they have some application mechanism to recover data loss.

Hint 43

Reference: CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press,
ISBN 1-58720-094-5) Page 161.

Front 44

Which IOS user EXEC command will allow a network technician to determine
which router in the path to an unreachable network host should be examined more
closely for the cause of the network failure?
A. Certkiller B> telnet
B. Certkiller B > ping
C. Certkiller B > trace
D. Certkiller B > show ip route
E. Certkiller B > show interface
F. Certkiller B > show cdp neighbors

Back 44

Answer: C
Explanation:
This can perform the trace command. It sends the ping packets to each of the routers on
the way to the receiver. The router which doesn't respond will be a potential failure place
in this network.

Front 45

You are logged into a router and wish to view the layer 3 information about your
neighboring Cisco routers. What IOS command gives layer 3 information for of the
directly connected router interfaces?
A. show ip links
B. show cdp neighbor
C. show cdp neighbor detail
D. show ip clients
E. show ip route
F. None of the above

Back 45

Answer: C
Explanation:
To display detailed information about neighboring devices discovered using Cisco
Discovery Protocol (CDP), use the show cdp neighbors privileged EXEC command.
Detail - (Optional) Displays detailed information about a neighbor (or neighbors)
including network address, enabled protocols, hold time, and software version.

Hint 45

Incorrect Answers:
A, D. These are invalid commands.
B. The "show cdp neighbor" command, without the "detail" keyword will not display the additional layer 3 protocol information.
E. This will show all routes from all other routers within the domain. We wish to see
information from just the direct interface neighbors.

Front 46

A Certkiller technician is troubleshooting connectivity problems between two
routers that are directly connected through the serial line. The technician notices
that the serial line is up but cannot see any neighbors displayed in the output of the
show cdp neighbors command.
In which OSI layer is the problem most likely occurring?
A. Physical
B. Data link
C. Network layer
D. Transport layer
E. Application layer

Back 46

Answer: B
Explanation:
As the question states that serial line is up, it means the problem is not on the Network
layer. The administrator cannot see any output by issuing the show cdp neighbors
command. It means that CDP is disabled and CDP is a protocol that runs over Layer2
(the data link layer) on all Cisco routers, bridges, access servers, and switches.

Front 47

While troubleshooting a network connectivity problem, a Certkiller technician
observes steady link lights on both the workstation NIC and the switch port to
which the workstation is connected. However, when the ping command is issued
from the workstation, the output message "Request timed out." is displayed. At
which layer of the 7-layer OSI model does the problem most likely exist?
A. The data link layer
B. The application layer
C. The protocol layer
D. The access layer
E. The session layer
F. The network layer
G. None of the above

Back 47

Answer: F
Explanation:
Network Layer:
The Network layer (also called layer 3) manages device addressing, tracks the location of
devices on the network, and determines the best way to move data, which means that the
Network layer must transport traffic between devices that aren't locally attached. Routers
(layer 3 devices) are specified at the Network layer and provide the routing services
within an internetwork.
Request Time out, Destination Unreachable etc error comes from Network Layer
problem.

Front 48

Which line from the output of the show ip interface command indicates that there is
a Layer 1 problem?
A. Serial0/1 is up, line protocol is down
B. Serial0/1 is down, line protocol is down
C. Serial0/1 is up, line protocol is up
D. Serial0/1 is administratively down, line protocol is down
E. None of the above

Back 48

Answer: B
Explanation:
When the physical interface itself is down, then the problem is related to layer 1. When it
is up, but the line protocol is down, then the problem is related to layer 2.

Hint 48

Reference: http://www.cisco.com/univercd/cc/td/doc/cisintwk/itg_v1/tr1915.htm

Front 49

At which layer of the OSI model does the protocol that provides the information
displayed by the "show cdp neighbors" command operate?
A. Transport
B. Physical
C. Application
D. Data link
E. Network

Back 49

Answer: D
Explanation:
CDP is a device discovery protocol that runs over Layer 2 (the data link layer) on all
Cisco-manufactured devices (routers, bridges, access servers, and switches) and allows
network management applications to discover Cisco devices that are neighbors of already
known devices. With CDP, network management applications can learn the device type
and the Simple Network Management Protocol (SNMP) agent address of neighboring
devices running lower-layer, transparent protocols.

Front 50

Which three of the protocols below belong to the application layer? (Select three
answer choices)
A. ARP
B. HTTPS
C. SMTP
D. CDP
E. TFTP
F. ICMP

Back 50

Answer: B, C, E
Explanation:
The application layer is the highest OSI layer, and protocols at this layer are end-user
oriented. HTTPS so people can get information on the internet, SMTP so people can
manage networks, and TFTP so people can download files.
Incorrect Answers:
A, D, F. ARP, CDP, ICMP are protocols that equipment like routers and switches use to
communicate with themselves, and belong to lower levels on the model.

Front 51

You want to upgrade the Certkiller LAN so that all ports operate in full duplex
mode. Which statement is true about full-duplex Ethernet when comparing to
half-duplex Ethernet?
A. Full-duplex Ethernet consists of a shared cable segment. Half-duplex provides a
point-to-point link
B. Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses
one wire to send and receive
C. Full-duplex Ethernet can provide higher throughput than can half-duplex Ethernet of
the same bandwidth
D. Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex Ethernet
uses a jam signal
E. None of the above

Back 51

Answer: C
Explanation:
Full-duplex Ethernet uses two pairs of wires instead of one wire pair like half duplex.
And full duplex uses a point-to-point connection between the transmitter of the transmitting device and the receiver of the receiving device. This means that with
full-duplex data transfer, you get a faster data transfer compared to half duplex.

Front 52

What are two characteristics of "store and forward" switching? (Select two answer
choices)
A. Latency fluctuates regardless of frame size.
B. The switch receives the complete frame before beginning to forward it.
C. Latency through the switch varies with frame length.
D. The switch checks the destination address upon receipt of headers.

Back 52

Answer: B, C
Explanation:
With store-and-forward, the entire frame is received by the switch before the first bit of
the frame is forwarded.
As soon as the incoming switch port receives enough of the frame to see the destination
MAC address, the forwarding decision is made and the frame is transmitted out the
appropriate outgoing port to the destination device. So, each frame might experience
slightly less latency. Store and forward switching may add latency when compared to
other switching methods such as cut through, but it can reduce the amount of errors that
become forwarded through a network.

Hint 52

Reference:
CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press, ISBN
1-58720-094-5) Page 243
Incorrect Answers:
A. The amount of latency that is introduced with this method of switching is dependent
on the size of the frame, as the switch must wait to receive the entire frame before
sending it.
D. The switch must wait for the entire frame before forwarding it on, and not just the
headers.

Front 53

Split horizon has been enabled within the Certkiller routed network. Which one of
the following statements best explains the split horizon rule?
A. Only routers can split boundaries (horizons) between networks in separate AS
numbers.
B. Each AS must keep routing tables converged to prevent dead routes from being
advertised across boundaries.
C. Once a route is received on an interface, advertise that route as unreachable back out
the same interface.
D. Information about a route should never be sent back in the direction from which the
original update came.
E. None of the above

Back 53

Answer: D
Explanation:
The split horizon rule states:
* Never advertise a route out of the interface through which you learned it.
For instance, in Figure 4a below, if Router One is connected to Routers Two and Three
through a single multipoint interface (such as Frame Relay), and Router One learned
about Network A from Router Two, it will not advertise the route to Network A back out
the same interface to Router Three. Router one assumes that Router Three would learn
about Network A directly from Router Two.
Incorrect Answers:
A: There is no such requirement
B: Distance vector protocols updates routing table at regular intervals instead of
Topology changes
C: This is the definition of the poison reverse rule, not the split horizon rule.

Hint 53

Reference: Wendell Odom. CISCO CCNA Certification Guide (2000 Press) Page 369.

Front 54

Which of the following commands would be applied to a WAN interface, but not on
LAN Interface? (Choose all that apply)
A. IP address
B. encapsulation PPP
C. no shutdown
D. authentication CHAP
E. Speed
F. None of the above

Back 54

Answer: B, D
Explanation:
PPP encapsulation can be used in ISDN interfaces, Asynchronous serial interfaces, and
point to point serial WAN connections. PPP is not an option for LAN interfaces. CHAP
authentication is a PPP 3 way authentication method. CHAP authentication can only be
used on PPP encapsulated interfaces and is not a LAN interface configuration option.

Hint 54

Incorrect Answers:
A, C. This command can be applied to both LAN and WAN interface types.
E. The speed command is used on LAN interfaces, and is not used on WAN interface
types.

Front 55

What kind of cable should be used to establish a trunked line between two Catalyst
switches?
A. A straight-through cable
B. An EIA/TIA-232 serial cable
C. An auxiliary cable
D. A modem cable
E. A cross-over cable

Back 55

Answer: E
Explanation:
A crossover cable is used to connect two of the same device types, or devices from the
same OSI layer.

Front 56

Assuming you build networks to exact specifications, what is the recommended
maximum length a 10BaseT cable can be before it has to be segmented or repeated?
A. 100 meters
B. 100 feet
C. 100 yards
D. 200 meters
E. None of the above

Back 56

Answer: A
Explanation:
The distance standards are in meters and 10BaseT has a distance restriction of 100
meters. If you go further then that, you compromise data integrity. 10BastT is the
predominant cable type used in Ethernet networks.

Front 57

statement is true about full-duplex Ethernet in comparison to half-duplex Ethernet?
A. Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses
one wire to send and receive
B. Full-duplex Ethernet consists of a shared cable segment. Half-duplex Ethernet
provides a point-to-point link
C. Full-duplex Ethernet can provide higher throughout than can half-duplex Ethernet of
the same bandwidth
D. Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex ethernet
uses a jam signal
E. None of the above

Back 57

Answer: C

Front 58

A network administrator wants to control which user hosts can access the network
based on their MAC address. What will prevent workstations with unauthorized
MAC addresses from connecting to the network through a switch?
A. BPDU
B. Port security
C. RSTP
D. STP
E. VTP
F. Blocking mode

Back 58

Answer: B
Explanation:
UnderstandingHow PortSecurity Works:
You can use port security to block input to an Ethernet, Fast Ethernet, or Gigabit Ethernet
port when the MAC address of the station attempting to access the port is different from
any of the MAC addresses specified for that port. Alternatively, you can use port security
to filter traffic destined to or received from a specific host based on the host MAC
address.
When a secure port receives a packet, the source MAC address of the packet is compared
to the list of secure source addresses that were manually configured or autoconfigured
(learned) on the port. If a MAC address of a device attached to the port differs from the
list of secure addresses, the port either shuts down permanently (default mode), shuts
down for the time you have specified, or drops incoming packets from the insecure host.
The port's behavior depends on how you configure it to respond to a security violation.
If a security violation occurs, the Link LED for that port turns orange, and a link-down
trap is sent to the Simple Network Management Protocol (SNMP) manager. An SNMP
trap is not sent if you configure the port for restrictive violation mode. A trap is sent only
if you configure the port to shut down during a security violation.

Hint 58

Reference:
http://www.cisco.com/en/US/products/hw/switches/ps700/products_configuration_guide_chapter09186a008007
f

Front 59

What is the IEEE standard associated with Gigabit Ethernet? (Select two answer
choices)
A. 802.11
B. 802.5
C. 802.3ab
D. 802.3ae
E. 802.3z
F. 802.3u

Back 59

Answer: C, E
Explanation:
The IEEE 802.3z standard describes 1000BASE-SX.
The 1000BaseT standard was released in June 1999, defined by IEEE 802.3ab.
Incorrect Answers:
A. This describes the standard used for wireless networks.
B. This is the standard for token ring networks.
D. On June 17, 2002 the IEEE 802.3ae specification for 10 Gigabit Ethernet was
approved as an IEEE standard by the IEEE Standards Association (IEEE-SA) Standards
Board.
F. IEEE 802.3u describes the standard for 100BASE-TX.

Front 60

Which of the following can lead to the contribution of LAN traffic congestion?
(Select all that apply)
A. Too many hosts in a broadcast domain
B. Full duplex operation
C. Broadcast storms
D. Multicasting
E. Segmentation
F. Low bandwidth

Back 60

Answer: A, C, F
Explanation:
Choice A is correct because the more hosts on a broadcast domain, the more traffic that is
created. Choice Ccontributes to congestion because broadcast storms can become very
problematic, and lead to complete network saturation. Multicasts are similar to
broadcasts in their use on a LAN. Finally, if there is not enough bandwidth, traffic
sessions can time out. This leads to new transmissions and the re-sending of data, which
can lead to more congestion.
Incorrect Answers:
B, E. These are incorrect because full duplex operation and segmented networks actually
result in less congestion.
D. Multicasting can actually alleviate congestion issues, as single streams of information
can reach multiple hosts at the same time, instead of using a series of point to point
connections.

Front 61

On a half-duplex Ethernet LAN, two hosts attempt to send data simultaneously,
resulting in a collision. Following this collision, what will the hosts do? (Select all
valid answers)
A. The destination host sends a request to the source for retransmission.
B. The jam signal indicates that the collision has been cleared.
C. The hosts will attempt to resume transmission after a time delay has expired.
D. An electrical pulse indicates that the collision has cleared.
E. The router on the segment will signal that the collision has cleared.
F. The hosts will do nothing, as the higher layers are responsible for data error correction
and re-transmission.

Back 61

Answer: C
Explanation:
When a host on an Ethernet LAN has information to send, the following steps are taken:
1. A device with a frame to send listens until Ethernet is not busy.
2. When the Ethernet is not busy, the sender begins sending the frame.
3. The sender listens to make sure that no collision occurred.
4. Once the senders hear the collision, they each send a jamming signal, to ensure that all
stations recognize the collision.
5. After the jamming is complete, each sender randomizes a timer and waits that long.
6. When each timer expires, the process starts over with step 1.

Front 62

Which of the following statements correctly describe the differences between
half-duplex and full-duplex Ethernet? (Select two answer choices.)
A. Full-duplex Ethernet uses CSMA/CD to prevent collisions.
B. Half-duplex Ethernet uses a loopback circuit to detect collisions.
C. A full-duplex Ethernet card allows 20Mbps for data transmission.
D. Full-duplex Ethernet makes use of two pairs of wires for data.
E. An Ethernet hub can operate both half and full duplex simultaneously.

Back 62

Answer: B, D
Explanation:
Half-duplex Ethernet send and receives on the same line, so a loopback needs to be set to
detect collisions. Alternatively, full-duple Ethernet doesn't have to because it uses two
pairs of wire, one to send and the other to receive. Collisions are not possible on full duplex Ethernet networks.

Hint 62

Incorrect Answers:
A. Full duplex uses both pairs of wires, so transmissions are sent on the first pair, and
data that is received come in on the other pair. This prevents collisions.
C. Full duplex allows for data to be sent and received at the same time. It will not double
the amount of bandwidth at any given time. The speed of the Ethernet link will remain at
10/100.
E. Hubs are shared devices and can only support one mode, unlike switches.

Front 63

Why is full-duplex Ethernet superior to its single-duplex counterpart? (Select two
answer choices.)
A. It uses inexpensive hubs
B. It operates without collisions
C. It operates on switches
D. It provides faster data transfer
E. It utilizes fewer wiring pairs

Back 63

Answer: B, D
Explanation:
Full duplex Ethernet allows concurrent sending and receiving, which allows the full
bandwidth to be used for both sending and receiving. The result is a collision free
network with increased throughput.

Hint 63

Incorrect Answers:
A, C. These are incorrect because full duplex doesn't require hubs or switches. Full
duplex operation can be used on switch and router ports, as well as PC hosts.
E. This is incorrect because full duplex actually uses more wiring pairs. In full duplex,
both wire pairs are used. Half duplex uses only a single pair.

Front 64

When you compare the differences between half-duplex and full-duplex Ethernet,
which of the following characteristics are exclusive to half-duplex? (Select two
answer choices)
A. Half-duplex Ethernet operates in a shared collision domain.
B. Half-duplex Ethernet operates in an exclusive broadcast domain.
C. Half-duplex Ethernet has efficient throughput.
D. Half-duplex Ethernet has lower effective throughput.
E. Half-duplex Ethernet operates in an exclusive collision domain.

Back 64

Answer: A, D
Explanation:
A single device could not be sending a frame and receiving a frame at the same time
because it would mean that a collision was occurring. So, devices simply chose not to
send a frame while receiving a frame. That logic is called half-duplex logic.
Ethernet switches allow multiple frames to be sent over different ports at the same time.
Additionally, if only one device is connected to a switch port, there is never a possibility
that a collision could occur. So, LAN switches with only one device cabled to each port
of the switch allow the use of full-duplex operation. Full duplex means that an Ethernet
card can send and receive concurrently.

Hint 64

Incorrect Answers:
B. Full duplex effectively doubles the throughput of half-duplex operation, because data
can be both sent and received at the full 10/100 speed.
C, E. In half duplex operation, the network is shared between all devices in the collision
domain.
Reference: CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press,
ISBN 1-58720-094-5) Page 62-63.

Front 65

Two stations on the Certkiller LAN transmit at the same time, resulting in a
collision. What happens when a collision occurs on the network? (Choose all that
apply)
A. Each device on the Ethernet segment stops transmitting for a short time.
B. A jam signal informs all devices that a collision occurred.
C. When data transmission resumes, the devices that were involved in the collision have
priority to transmit.
D. The devices that are involved in the collision stops transmitting for a short time.
E. The collision invokes a random back-off algorithm.

Back 65

Answer: B, D, E
Explanation:
When a host on an Ethernet LAN has information to send, the following steps are taken:
1. A device with a frame to send listens until Ethernet is not busy.
2. When the Ethernet is not busy, the sender begins sending the frame.
3. The sender listens to make sure that no collision occurred.
4. Once the senders hear the collision, they each send a jamming signal, to ensure that all
stations recognize the collision.
5. After the jamming is complete, each sender randomizes a timer and waits that long.
6. When each timer expires, the process starts over with step 1.

Hint 65

Incorrect Answers:
A. Only the stations involved in the collision stop transmitting for a short time, not all
stations on the LAN.
C. No priority is given to any stations once a collision has occurred.

Front 66

Which of the following are true of Ethernet technology?
A. Hosts use a logical ring topology.
B. Hosts use a logical bus topology
C. Hosts must wait for an electronic signal to transfer data.
D. Hosts are directly connected to a wiring concentrator called a MSAU.
E. None of the above

Back 66

Answer: B
Explanation:
LAN topologies define the manner in which network devices are organized. Four
common LAN topologies exist: bus, ring, star, and tree. These topologies are logical
architectures, but the actual devices need not be physically organized in these
configurations. Logical bus and ring topologies, for example, are commonly organized
physically as a star. A bus topology is a linear LAN architecture in which transmissions
from network stations propagate the length of the medium and are received by all other
stations. Of the three most widely used LAN implementations, Ethernet/IEEE 802.3
networks, including 100BaseT, implement a bus topology, which is illustrated in Figure
2-3.
Figure2-3: Some networks implement a local bus topology.

Hint 66

Reference: http://www.pulsewan.com/lanintro.htm

Front 67

With regard to Ethernet media access methods, which of the following are true?
(Choose all that apply.)
A. A device waits for an electronic signal before transmitting.
B. A device listens and waits until the media is not busy before transmitting.
C. All devices on an Ethernet segment see data that passes on the network medium.
D. Only the sender and the receiver devices see data that passes on the network medium.
E. Ethernet networks allow you to configured devises with higher transmission priority.

Back 67

Answer: B, C
Explanation:
Ethernet uses the CSMA/CD access method.
CSMA/CD logic helps prevent collisions and also defines how to act when a collision
does occur. The CSMA/CD algorithm words like this:
1. A device with a frame to send listens until the Ethernet is not busy.
2. When the Ethernet is not busy, the sender begins sending the frame.
3. The sender listens to make sure that no collision occurred.
4. Once the senders hear the collision, they each send a jamming signal, to ensure that all
stations recognize the collision.
5. After the jamming is complete, each sender randomizes a timer and waits that long.
6 When each timer expires, the process starts over with Step 1.
So, all devices on the Ethernet need to use CSMA/CD to avoid collisions and to recover
when inadvertent collisions occur.

Hint 67

Reference: Cisco CCNA intro 640-821 p.55

Front 68

Which two statements describe the operation of the CSMA/CD access method,
which is in use on the Certkiller network? (Choose two)
A. After a collision, the station that detected the collision has first priority to resend the
lost data.
B. In a CSMA/CD collision domain, stations must wait until the media is not in use
before transmitting.
C. In a CSMA/CD collision domain, multiple stations can successfully transmit data
simultaneously.
D. The use of hubs to enlarge the size of collision domains is one way to improve the
operation of the CSMA/CD access method.
E. After a collision, all stations run a random backoff algorithm. When the backoff delay
period has expired, all stations have equal priority to transmit data.
F. After a collision, all stations involved run an identical backoff algorithm and then
synchronize with each other prior to transmitting data.

Back 68

Answer: B, E
Explanation:
Ethernet networking uses Carrier Sense Multiple
Access with Collision Detect (CSMA/CD), a protocol
that helps devices share the bandwidth evenly
without having two devices transmit at the same time
on the network medium. CSMA/CD was created to
overcome the problem of those collisions that occur when
packets are transmitted simultaneously from different nodes. And trust me, good collision
management is crucial, because when a node transmits in a CSMA/CD network, all the other nodes on the network receive and examine that transmission. Only bridges and
routers can effectively prevent a transmission from propagating throughout the entire
network! So, how does the CSMA/CD protocol work? Like this: when a host wants to
transmit over the network, it first checks for the presence of a digital signal on the wire.
If all is clear (no other host is transmitting), the host will then proceed with its
transmission. But it doesn't stop there. The transmitting host constantly monitors the wire
to make sure no other hosts begin transmitting. If the host detects another signal on the
wire, it sends out an extended jam signal that causes all nodes on the segment to stop
sending data (think, busy signal). The nodes respond to that jam signal by waiting a while
before attempting to transmit again. Backoff algorithms determine when the colliding
stations can retransmit. If collisions keep occurring after 15 tries, the nodes attempting to
transmit will then time out.

Front 69

Which three statements are true about the operation of a full-duplex Ethernet
network, which is being used in the Certkiller LAN? (Choose three)
A. Ethernet hub ports are preconfigured for full-duplex mode.
B. The host network card and the switch port must be capable of operating in full-duplex
mode.
C. There are no collisions in full-duplex mode.
D. In a full-duplex environment, the host network card must check for the availability of
the network media before transmitting.
E. A dedicated switch port is required for each full-duplex node.

Back 69

Answer: B, C, E
Explanation:
Half-duplex Ethernet is defined in the original 802.3 Ethernet and Cisco says you only
use one wire pair with a digital signal running in both directions on the wire. It also uses
the CSMA/CD protocol to help prevent collisions and to permit retransmitting if a
collision does occur. If a hub is attached to a switch, it must operate in half-duplex mode
because the end stations must be able to detect collisions. Half-duplex Ethernet-typically
10BaseT-is only about 30 to 40 percent efficient as Cisco sees it, because a large
10BaseT network will usually only give you 3- to 4Mbps-at most.
Full-duplex Ethernet uses two pairs of wires, instead of one wire pair like half duplex.
Also, full duplex uses a point-to-point connection between the transmitter of the
transmitting device and the receiver of the receiving device, which means that with
full-duplex data transfer, you get a faster data transfer compared to half duplex. And
because the transmitted data is sent on a different set of wires than the received data, no
collisions occur. The reason you don't need to worry about collisions is because now
Full-duplex Ethernet is like a freeway with multiple lanes instead of the single-lane road
provided by half duplex. Full-duplex Ethernet is supposed to offer 100 percent efficiency in both directions; this means you can get 20Mbps with a 10Mbps Ethernet running full
duplex, or 200Mbps for FastEthernet.

Front 70

The Certkiller network administrator wants to use a router named CK1 to segment
the local network. What are some of the advantages of using CK1 to segment the
network? (Choose two)
A. Routers generally cost less than switches
B. Filtering can occur based on Layer 3 information
C. Broadcasts are not forwarded across the router
D. Broadcasts are eliminated
E. Adding a router to the network decreases latency
F. Routers can generally support more LAN ports than switches

Back 70

Answer: B, C
Explanation:
When the router's interface receives the broadcast, it discard the broadcast without
forwarding it on to other networks. Even though routers are known for breaking up
broadcast domains by default, it's important to remember that they break up collision
domains as well.
There are two advantages of using routers in your network:
* They don't forward broadcasts by default.
* They can filter the network based on layer 3 (Network layer) information (e.g., IP
address) by using IOS based firewall ie. ACL
Four router functions in your network can be listed as follows:
* Packet switching
* Packet filtering
* Internetwork communication
* Path selection

Front 71

Which of the following devices can the Certkiller network administrator use to
segment the LAN? (Choose all that apply)
A. Hubs
B. Repeaters
C. Switches
D. Bridges
E. Routers
F. Media Converters
G. All of the above

Back 71

Answer: C, D, E
Explanation:
Switches and bridges forward broadcast but routers do not forward broadcasts by default
(they can via the "ip helper-address" command).
Switches, bridges and routers can segment an Ethernet collision domain via the use of
VLAN's

Hint 71

Incorrect Answers:
A. Hubs is incorrect because a hub doesn't segment a network, it only allows more hosts
on one. Hubs operate at layer one, and is used primarily to physically add more stations
to the LAN.
B. This also incorrect because the job of a repeater is to repeat a signal so it can exceed
distance limitations. It also operates at layer one and provides no means for logical LAN
segmentation.
F. This is incorrect because media converters work by converting data from a different
media type to work with the media of a LAN. It also operates at layer one and provides
no means for logical LAN segmentation.

Front 72

The Certkiller corporate LAN consists of one large flat network. You decide to
segment this LAN into two separate networks with a router. What will be the affect
of this change?
A. The number of broadcast domains will be decreased.
B. It will make the broadcasting of traffic between domains more efficient between
segments.
C. It will increase the number of collisions.
D. It will prevent segment 1's broadcasts from getting to segment 2.
E. It will connect segment 1's broadcasts to segment 2.

Back 72

Answer: D
Explanation
A router does not forward broadcast traffic. It therefore breaks up a broadcast domain,
reducing unnecessary network traffic. Broadcasts from one segment will not be seen on
the other segment.

Hint 72

Incorrect Answers:
A. This will actually increase the number of broadcast domains from one to two.
B. All link level traffic from segment one to segment two will now need to be routed
between the two interfaces of the router. Although this will reduce the traffic on the LAN
links, it does also provide a less efficient transport between the segments.
C. Since the network size is effectively cut into half, the number of collisions should
decrease dramatically.
E. Broadcasts from one segment will be completely hidden from the other segment.

Front 73

You want to influence the root bridge selection within the Certkiller LAN. Which
two values are used by spanning tree protocol to elect a root bridge? (Choose two.)
A. Amount of RAM
B. Speed of the links
C. IOS Version
D. MAC Address
E. Bridge Priority
F. IP Address
G. Router ID

Back 73

Answer: D, E
Explanation:
Switch having lowest bridge ID will become the root bridge. The bridge ID is how STP
keeps track of all the switches in the network. It is determined by a combination of the
bridge priority (32,768 by default on all Cisco switches) and the base MAC address. The
bridge with the lowest bridge ID becomes the root bridge in the network.

Front 74

A Certkiller Ethernet switch receives a unicast frame with a destination MAC that
IS listed in the switch table. What will this switch do with the frame?
A. The switch will forward the frame to a specific port
B. The switch will forward the frame to all ports except the port on which it was received
C. The switch will return a copy of the frame out the source port
D. The switch will not forward unicast frames
E. The switch will remove the destination MAC from the switch table
F. None of the above.

Back 74

Answer: A
Explanation:
How Does the Switch Find Host MACs?
Let's use the diagram below to help us understand how address learning process takes
place.
Let's assume that we have just powered on the switch. It has nothing in its MAC table.
We connect the cables from the hosts on the switch interfaces as shown in the diagram.
Host A initiates a connection towards Host D, and the following takes place:
1. Host A (interface fe0/0) sends a frame to Host D (MAC address:0000.43c5.334c).
2. The switch inspects the Source Address in the frame and notes in its table the MAC
address of Host A along with the Interface number from which the frame originated.
3.
The switch inspects the Destination Address in the frame. Since it does not have Hosts D
MAC address in its table, it constructs a broadcast frame and forwards out all interfaces
except the interface from where the original frame arrived.
4. Host D identifies itself as the expected recipient and responds back to Host
A. The
switch receives the respond frame on interface fe0/11 and places the SA in its table along
with the interface number where the frame came from.
5. From now on, further communication between the two hosts will be switched to
the appropriate interfaces based on the MAC tables entries.
This process takes place every time a new host is attached on the switch and initiates
traffic. The switch tries to keep its MAC table up-to-date, therefore if some hosts do not
initiate traffic for a certain amount of time, the switch removes them from its table and
reinserts them when they begin sending traffic.

Hint 74

Reference:
http://www.trainsignaltraining.com/studying-for-your-ccent-learn-all-about-switching-and-stp/2007-11-01/

Front 75

In which circumstance are multiple copies of the same unicast frame likely to be
transmitted in the Certkiller Switched LAN?
A. During high traffic periods
B. In an improperly implemented redundant topology
C. After broken links are re-established
D. When upper-layer protocols require high reliability
E. When a dual ring topology is in use
F. None of the above

Back 75

Answer: B
Explanation:
A redundant topology eliminates single points of failure, but it also causes broadcast
storms, multiple frame copies, and MAC address table instability problems. Multiple
Frame Copies--when a new switch is added, the other switches may not have learned its
correct MAC address. The host may send a unicast frame to the new switch. The frame is
sent through several paths at the same time. The new switch will receive several copies of
the frame. This causes MAC database instability. MAC database instability results when
multiple copies of a frame arrive on different ports of a switch. Layer 2 has no
mechanism to stop the loop. This is the main reason for the Spanning Tree Protocol(STP)
IEEE 802.1d which was developed to prevent routing loops.
If multiple connections between switches are created for redundancy purposes, network
loops can occur in an improperly designed topology. Spanning Tree Protocol (STP) is
used to stop network loops while still permitting redundancy.

Front 76

The Certkiller network administrator needs to a switch named CK1 to become the
root bridge for a redundant path switched network. What can be done to ensure
that CK1 will always assume the role as the root bridge?
A. Assign the switch a higher MAC address than the other switches in the network have
B. Establish a direct link from the switch to all other switches in the network
C. Configure the switch full-duplex operation and configure the other switches for
half-duplex operation
D. Configure the switch so that it has lower priority than other switches in the network
E. None of the above

Back 76

Answer: D
Explanation:
Switch having lowest bridge ID will become the root bridge. The bridge ID is how STP
keeps track of all the switches in the network. It is determined by a combination of the
bridge priority (32,768 by default on all Cisco switches) and the base MAC address. The
bridge with the lowest bridge ID becomes the root bridge in the network. To elect the
desired switch as a root bridge, set the bridge priority lowest than other switch.

Front 77

CK1 is a switch in the Certkiller network. Why will CK1 never learn the broadcast
address?
A. Broadcast frames are never sent to switches
B. A broadcast frame is never forwarded by a switch
C. Broadcasts only use network layer addressing
D. A broadcast address will never be the source address of a frame
E. Broadcast addresses use an incorrect format for the switching table
F. None of the above

Back 77

Answer: D
Explanation:
There are three different address types:
* Unicast : One source to One destination
* Broadcast: One source to multiple destination
* Multicast: One source to multiple destination joined to group
On unicast or broadcast or multicast communication, the source address is always the
unicast address but the destination address can be unicast, broadcast or multicast.

Front 78

The system LED is amber on a new Certkiller Catalyst 2950 series switch. What does
this indicate?
A. The system is powered up and operational.
B. The system is sensing excessive collisions.
C. The system is forwarding traffic.
D. The system is not powered up.
E. The system is malfunctioning.
F. None of the above

Back 78

Answer: E
Explanation:
While the switch powers on, it begins POST, a series of tests. POST runs automatically
to verify that the switch functions properly. When the switch begins POST, the system
LED is off. If POST completes successfully, the LED turns green. If POST fails, the LED
turns amber.
Note: POST failures are usually fatal. Call Cisco Systems if your switch does not pass
POST.

Front 79

Some of the older Certkiller switches store the entire frame before forwarding it to
the destination. What are two effects on network performance of configuring a
switch to do this? (Choose two)
A. Filtering of collision fragments only
B. Decreased latency
C. Increased latency
D. Filtering of all frame errors
E. Increase in switch operating speed
F. Propagation of corrupted or damaged frames

Back 79

Answer: C, D
Explanation:
Switches that store the entire frame before forwarding to the destination are using the
store and forward process. This mode copies the entire frame into memory, computes the
Cyclic Redundancy Check (CRC) for errors, and then looks up the destination MAC
address and forwards the frame. This is slow but offers the best solution for error
correction without affecting the entire backbone in retransmission. This gives us the best
method for filtering errors from traversing the network, but at a cost of higher latency.

Front 80

As a Certkiller trainee you are required to set the default gateway on a Cisco switch
to the IP address of 192.168.1.115. Which IOS command should you use?
A. CertK Switch(config)# ip route-default 192.168.1.115
B. CertK Switch(config)# ip default-gateway 192.168.1.115
C. CertK Switch(config)# ip route 192.168.1.115 0.0.0.0
D. CertK Switch(config)# ip default-network 192.168.1.115
E. None of the above

Back 80

Answer: B
Explanation:
Use the "ip default-gateway" command to enter the IP address of the next-hop router
interface that is directly connected to the switch where a default gateway is being
configured. The default gateway receives IP packets with unresolved destination IP
addresses from the switch.
Once the default gateway is configured, the switch has connectivity to the remote
networks with which a host needs to communicate.

Front 81

You need to perform some initial configuration tasks on a new Certkiller switch.
What is the purpose of assigning an IP address to a switch?
A. To provide local hosts with a default gateway address
B. To allow remote management of the switch.
C. To allow the switch to respond to ARP requests between two hosts
D. To ensure that hosts on the same LAN can communicate with each other.
E. None of the above

Back 81

Answer: B
Explanation:
Switch is a layer 2 device and doesn't use network layer for packet forwarding. The IP address may be used only for administrative purposes such as Telnet access or for
network management purposes.

Front 82

You need to perform some initial configuration tasks on a new Certkiller switch.
What are the possible trunking modes for this switch port? (Choose three)
A. Transparent
B. Auto
C. On
D. Desirable
E. Client
F. Forwarding
G. Learning

Back 82

Answer: B, C, D
Explanation:
Here, the trunk link is identified by its physical location as the switch module number
and port number. The trunking mode can be set to any of the following:
on- This setting places the port in permanent trunking mode. The corresponding switch
port at the other end of the trunk should be similarly configured because negotiation is
not
allowed. The encapsulation or identification mode should also be manually configured.
off-This setting places the port in permanent non-trunking mod. the port will attempt
to convert the link to non-trunking mode.
desirable-Selection this port will actively attempt to convert the link into trunking
mode. If the far end switch port is configured to on, desirable, or auto mode, trunking
will be successfully negotiated.
auto-The port will be willing to convert the link into trunking mode. If the far end
switch
port is configured to on or desirable, trunking will be negotiated. By default, all Fast
Ethernet and Gigabit Ethernet links that are capable of negotiating using DTP are
configured to this mode. Because of the passive negotiation behavior, the link will never
become a trunk, if both ends of the link are left to the auto default.
nonegotiate-The port is placed in permanent trunking mode, but no DTP frames are
generated for negotiation. The far end switch port must be manually configured for
trunking mode.

Front 83

An administrator would like to configure a switch over a virtual terminal
connection from locations outside of the local LAN. Which of the following are
required in order for the switch to be configured from a remote location? (Choose
two)
A. The switch must be reachable through a port connected to its management VLAN.
B. The switch console port must be connected to the Ethernet LAN.
C. The switch must be fully configured as an SNMP agent.
D. The switch must be configured with an IP address, subnet mask, and default gateway.
E. The switch management VLAN must be created and have a membership of at least one
switch port.
F. The switch must be connected to a router over a VLAN trunk.

Back 83

Answer: A, D
Explanation:
In order the telnet to any Cisco device, the device must be reachable from the remote
location. For a Cisco switch to be reachable from remote locations, it must have an IP
address, subnet mask, and default gateway assigned.
Communication with the switch management interfaces is through the switch IP address.
The IP address is associated with the management VLAN, which by default is VLAN 1

Front 84

While troubleshooting a connectivity problem, the Certkiller network administrator
notices that a port status LED on a Cisco Catalyst Series switch is alternating
between green and amber. Which condition could this indicate?
A. The port is experiencing errors
B. The port has ac active link with normal traffic activity
C. The port blocked by spanning tree
D. The port is administratively disabled
E. None of the above

Back 84

Answer: A

Front 85

You are the administrator of the Certkiller LAN and you have been reviewing error
logs of networking devices and notice a large number of errors associated with
several MAC addresses. You suspect that some of the errors are being generated by
the routers. Which router commands will allow you to find the ip address associated
with each MAC address? (Choose two)
A. show arp
B. show version
C. show address
D. show hosts
E. show interface
F. show protocols

Back 85

Answer: A, E
Explanation:
The "show arp" command Displays the entries in the ARP table, including their layer 2
MAC address and layer 3 IP address.
Example:
The following is the output for the show arp command on Router 1:
CK1 # show arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.0.0.3 0 0004.dd0c.ffcb ARPA Ethernet01
Internet 10.0.0.1 - 0004.dd0c.ff86 ARPA Ethernet0
To see the MAC (hardware) address of the router interfaces as well as their IP addresses,
use the "show interfaces" command as shown in the example below:
CK1 # show interfaces
Ethernet 0 is up, line protocol is up
Hardware is MCI Ethernet, address is 0000.0c00.750c (bia 0000.0c00.750c)
Internet address is 10.108.28.8, subnet mask is 255.255.255.0
MTU 1500 bytes, BW 10000 Kbit, DLY 100000 usec, rely 255/255, load 1/255

Front 86

The Certkiller network administrator issues the ping 192.168.2.5 command and
successfully tests connectivity to a host that has been newly connected to the
network. Which protocols were used during the test? (Choose two)
A. ARP
B. CDP
C. DHCP
D. DNS
E. ICMP

Back 86

Answer: A, E
Explanation:
ARP finds the hardware address of a host from a known IP address. Here's how it works:
when IP has a datagram to send, it must inform a Network Access protocol, such as
Ethernet or Token Ring, of the destination's hardware address on the local network. (It
has already been informed by upper-layer protocols of the destination's IP address.) If IP
doesn't find the destination host's hardware address in the ARP cache, it uses ARP to find
this information.
ICMP works at the Network layer and is used by IP for many different services. ICMP is
a management protocol and messaging service provider for IP. Its messages are carried as
IP datagrams. RFC 1256 is an annex to ICMP, which affords hosts' extended capability in
discovering routes to gateways. Periodically, router advertisements are announced over
the network, reporting IP addresses for the router's network interfaces. Hosts listen for
these network infomercials to acquire route information. A router solicitation is a request
for immediate advertisements and may be sent by a host when it starts up.

Front 87

While troubleshooting an issue in the Certkiller LAN you notice that a network
interface port has collision detection and carrier sensing enabled on a shared
twisted pair network. From this statement, what is known about the network
interface port?
A. This is an Ethernet port operating at half duplex
B. This is an Ethernet port operating at full duplex
C. This is a port on a network interface card in a PC
D. This is 10 MB/s switch port
E. This is a 100 MB/s switch port
F. None of the above

Back 87

Answer: A
Explanation:
Half-duplex Ethernet is defined in the original 802.3 Ethernet; Cisco says it uses only one
wire pair with a digital signal running in both directions on the wire.
It also uses the CSMA/CD protocol to help prevent collisions and to permit retransmitting if a collision does occur. If a hub is attached to a switch, it must operate in
half-duplex mode because the end stations must be able to detect collisions. Half-duplex
Ethernet-typically 10BaseT-is only about 30 to 40 percent efficient as Cisco sees it
because a large 10BaseT network will usually only give you 3 to 4Mbps, at most

Front 88

When a switch port is used as a VLAN trunk, which of the following trunk modes
are valid? (Select all that apply.)
A. Blocking
B. Auto
C. Desirable
D. On
E. Transparent
F. Learning

Back 88

Answer: B, C, D
Explanation:
A trunk port can be configured as one of the following 5 different modes: on, off,
desirable, auto, or nonegotiate.

Front 89

Which of following VLAN frame encapsulation types are configurable on a Cisco
switch? (Select two answer choices.)
A. VTP
B. 802.1Q
C. LLC
D. ISL
E. CDP
F. PAP

Back 89

Answer: B, D
Explanation:
ISL and 802.1Q are the two trunking encapsulations that can be configured on a Cisco
switch. ISL is Cisco proprietary and 802.1Q is the IEEE standard method.

Hint 89

Incorrect Answers:
A. VTP is the VLAN Trunking Protocol, which is used to carry VLAN information
across the trunks. The question is asking for the encapsulation options for the trunk,
which will be used by VTP.
C. LLC is the Logical Link Control, which is a sub-layer of the data link layer.
E. CDP is the Cisco Discovery Protocol, which is used by Cisco devices to discover
information on neighboring Cisco devices.
F. PAP is the Password Authentication Protocol, which is used as an authentication
mechanism on PPP links.

Front 90

Certkiller users have noticed extremely slow network performance, intermittent
connectivity, and connection losses. After entering the "show interfaces" command,
you notice that the Ethernet interface is configured as 100 Mbps full-duplex and
that there is evidence of late collisions. What could be the cause of this problem?
A. Duplex mismatch
B. A routing loop
C. Trunking mode mismatch
D. Improperly configured root bridge
E. Improperly configured static VLAN
F. None of the above

Back 90

Answer: A
Explanation:
A duplex mismatch may result in performance issues, intermittent connectivity, and loss
of communication. When troubleshooting NIC issues, verify that the NIC and switch are
using a valid configuration. Some third-party NIC cards may fall back to half-duplex
operation mode, even though both the switchport and NIC configuration have been
manually configured for 100 Mbps, full-duplex. This behavior is due to the fact that NIC
autonegotiation link detection is still operating when the NIC has been manually
configured. This causes duplex inconsistency between the switchport and the NIC.
Symptoms include poor port performance and frame check sequence (FCS) errors that
increment on the switchport. To troubleshoot this issue, try manually configuring the
switchport to 100 Mbps, half-duplex. If this action resolves the connectivity
problems,you may be running into this NIC issue. Try updating to the latest drivers for
your NIC, or contact your NIC card vendor for additional support.

Hint 90

Reference:
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00800a7af0.shtml

Front 91

You are experiencing intermittent issues relating to congestion within the Certkiller
network. What are the possible causes of congestion on this LAN? (Choose all that
apply)
A. A broadcast domain with too many hosts.
B. Full duplex operation.
C. Broadcast storms.
D. Multicasting.
E. Network Segmentation.
F. Low bandwidth.

Back 91

Answer: A, C, F
Explanation:
A LAN segment with too many hosts can mean that there are a large number of stations
contending for bandwidth. It can also mean an increase in the number of collisions on the
segment, which can cause further congestion issues. Broadcast storms are the result of a
large number of broadcasts sent over the LAN. Because each station listens to these
broadcast messages, congestion can occur quickly. Finally, low bandwidth can simply
mean that the LAN can not process all of the LAN traffic that is being sent. This can
mean that TCP sessions are retransmitted, which can lead to additional congestion.

Hint 91

Incorrect Answers:
B. This can alleviate congestion, as data can be sent and received at the same time. In
addition, collisions are not possible in a full duplex LAN.
D. Multicasting can actually alleviate congestion issues, as single streams of information
can reach multiple hosts at the same time, instead of using a series of point to point
connections.
E. Segmentation breaks up a large LAN into multiple, smaller LANS. This will mean
fewer hosts per broadcast domain.

Front 92

You need to configure two Certkiller switches to exchange VLAN information.
Which protocol provides a method of sharing VLAN configuration information
between these two switches?
A. STP
B. 802.1Q
C. VLSM
D. ISL
E. VTP
F. HSRP
G. None of the above

Back 92

Answer: E
Explanation:
VLAN Trunking Protocol (VTP) is a Cisco proprietary Layer 2 messaging protocol that
manages the addition, deletion, and renaming of VLANs on a network-wide basis.
Virtual Local Area Network (VLAN) Trunk Protocol (VTP) reduces administration in a
switched network. When you configure a new VLAN on one VTP server, the VLAN is
distributed through all switches in the domain. This reduces the need to configure the
same VLAN everywhere. To do this VTP carries VLAN information to all the switches
in a VTP domain. VTP advertisements can be sent over ISL, 802.1q, IEEE 802.10 and
LANE trunks. VTP traffic is sent over the management VLAN (VLAN1), so all VLAN
trunks must be configured to pass VLAN1. VTP is available on most of the Cisco
Catalyst Family products.

Front 93

Certkiller has implemented the use of the Virtual Trunking Protocol (VTP). Which
statement below accurately describes a benefit of doing this?
A. VTP will allow physically redundant links while preventing switching loops
B. VTP will allow switches to share VLAN configuration information
C. VTP will allow a single port to carry information to more than one VLAN
D. VTP will allow for routing between VLANs
E. None of the above

Back 93

Answer: B
Explanation:
Trunking Protocol (VTP) are to manage all configured VLANs across a switched
internetwork and to maintain consistency throughout that network VTP allows you to
add, delete, and rename VLANs-information that is then propagated to all other switches
in the VTP domain.
Here's a list of some features of VTP:
* Consistent VLAN configuration across all switches in the network
* VLAN trunking over mixed networks, such as Ethernet to ATM LANE or even FDDI
* Accurate tracking and monitoring of VLANs
* Dynamic reporting of added VLANs to all switches in the VTP domain
* Plug and Play VLAN adding

Front 94

A Certkiller switch is configured with all ports assigned to VLAN 2. In addition, all
ports are configured as full-duplex FastEthernet. What is the effect of adding switch
ports to a new VLAN on this switch?
A. The additions will create more collisions domains.
B. IP address utilization will be more efficient.
C. More bandwidth will be required than was needed previously.
D. An additional broadcast domain will be created.
E. The possibility that switching loops will occur will increase dramatically.

Back 94

Answer: D
Explanation:
A VLAN is a group of hosts with a common set of requirements that communicate as if
they were attached to the same wire, regardless of their physical location. A VLAN has
the same attributes as a physical LAN, but it allows for end stations to be grouped
together even if they are not located on the same LAN segment.
Networks that use the campus-wide or end-to-end VLANs logically segment a switched network based on the functions of an organization, project teams, or applications rather
than on a physical or geographical basis. For example, all workstations and servers used
by a particular workgroup can be connected to the same VLAN, regardless of their
physical network connections or interaction with other workgroups. Network
reconfiguration can be done through software instead of physically relocating devices.
Cisco recommends the use of local or geographic VLANs that segment the network
based on IP subnets. Each wiring closet switch is on its own VLAN or subnet and traffic
between each switch is routed by the router. The reasons for the Distribution Layer 3
switch and examples of a larger network using both the campus-wide and local VLAN
models will be discussed later.
A VLAN can be thought of as a broadcast domain that exists within a defined set of
switches. Ports on a switch can be grouped into VLANs in order to limit unicast,
multicast, and broadcast traffic flooding. Flooded traffic originating from a particular
VLAN is only flooded out ports belonging to that VLAN, including trunk ports, so a
switch that connects to another switch will normally introduce an additional broadcast
domain.

Front 95

A new switch is installed in the Certkiller network. This switch is to be configured so
that VLAN information will be automatically distributed to all the other Cisco
Catalyst switches in the network.
Which of the conditions below have to be met in order for this to occur? (Choose all
that apply).
A. The switch that will share the VLAN information must be in the VTP Server mode.
B. The switches must be in the same VTP domain.
C. The switch that will share the VLAN information must be configured as the root
bridge.
D. The switches must be configured to use the same VTP version.
E. The switches must be configured to use the same STP version.
F. The switches must be configured to use the same type of ID tagging.
G. The switches must be connected over VLAN trunks.

Back 95

Answer: A, B, F, G
Explanation:
For the VLAN information to pass automatically throughout the network, VTP must be
set up correctly. In order for VTP to work, a VTP server is needed, the VLAN's must be
in the same VTP domain, and the encapsulation on each end of the trunk must both set to
either 802.1Q or ISL.

Hint 95

Incorrect Answers:
C. Root bridges and other functions of the Spanning Tree Protocol (STP) have no impact
of the VTP configuration.
D, E. There is only one version of VTP and STP.

Front 96

A network administrator needs to force a high-performance switch that is located in
the MDF to become the root bridge for a redundant path switched network. What
can be done to ensure that this switch assumes the role of the Root Bridge?
A. Configure the switch so that it has a lower priority than other switches in the network.
B. Assign the switch a higher MAC address than the other switches in the network have.
C. Configure the switch for full-duplex operation and configure the other switches for
half-duplex operation.
D. Connect the switch directly to the MDF router, which will force the switch to assume
the role of root bridge.
E. Establish a direct link from the switch to all other switches in the network.
F. None of the above

Back 96

Answer: A
Explanation:
For all switches in a network to agree on a loop-free topology, a common frame of
reference must exist. This reference point is called the Root Bridge. The Root Bridge is
chosen by an election process among all connected switches. Each switch has a unique
Bridge ID (also known as the bridge priority) that it uses to identify itself to other
switches. The Bridge ID is an 8-byte value. 2 bytes of the Bridge ID is used for a Bridge
Priority field, which is the priority or weight of a switch in relation to all other switches.
The other 6 bytes of the Bridge ID is used for the MAC Address field, which can come
from the Supervisor module, the backplane, or a pool of 1024 addresses that are assigned
to every Supervisor or backplane depending on the switch model. This address is hard
coded, unique, and cannot be changed.
The election process begins with every switch sending out BPDUs with a Root Bridge ID
equal to its own Bridge ID as well as a Sender Bridge ID. The latter is used to identify
the source of the BPDU message. Received BPDU messages are analyzed for a lower
Root Bridge ID value. If the BPDU message has a Root Bridge ID (priority) of the lower
value than the switch's own Root Bridge ID, it replaces its own Root Bridge ID with the
Root Bridge ID announced in the BPDU. If two Bridge Priority values are equal, then the
lower MAC address takes preference.

Front 97

Which of the protocols below, operates at Layer 2 of the OSI model, and is used to
maintain a loop-free network?
A. RIP
B. STP
C. IGRP
D. CDP
E. VTP
F. None of the above

Back 97

Answer: B
Explanation:
STP (spanning tree protocol) operates on layer 2 to prevent loops in switches and
bridges.

Hint 97

Incorrect Answers:
A, C. RIP and IGRP are routing protocols, which are used at layer 3 to maintain a loop
free routed environment.
D. CDP does indeed operate at layer 2, but it doest not provide for a loop free topology.
CDP is used by Cisco devices to discover information about their neighbors.
E. VTP is the VLAN Trunking Protocol, used to pass VLAN information through
switches. It relies on the STP mechanism to provide a loop free network.

Front 98

By default, which of the following factors determines the spanning-tree path cost?
A. It is the individual link cost based on latency
B. It is the sum of the costs based on bandwidth
C. It is the total hop count
D. It is dynamically determined based on load
E. None of the above

Back 98

Answer: B
Explanation:
"The STP cost is an accumulated total path cost based on the available bandwidth of each
of the links."
Reference: Sybex CCNA Study Guide 4th Edition (Page 323)
Note: A path cost value is given to each port. The cost is typically based on a guideline
established as part of 802.1d. According to the original specification, cost is 1,000 Mbps
(1 gigabit per second) divided by the bandwidth of the segment connected to the port.
Therefore, a 10 Mbps connection would have a cost of (1,000/10) 100.
To compensate for the speed of networks increasing beyond the gigabit range, the
standard cost has been slightly modified. The new cost values are:
Bandwidth - STP Cost Value
4 Mbps - 250
10 Mbps - 100
16 Mbps - 62
45 Mbps - 39
100 Mbps - 19
155 Mbps - 14
622 Mbps - 6
1 Gbps - 4
10 Gbps - 2
You should also note that the path cost can be an arbitrary value assigned by the network
administrator, instead of one of the standard cost values.
Incorrect Answers:
A, D: The STP process does not take into account the latency or load of a link. STP does
not recalculate the link costs dynamically.
C. Hop counts are used by RIP routers to calculate the cost of a route to a destination.
The STP process resides at layer 2 of the OSI model, where hop counts are not
considered.

Front 99

What is the purpose of the spanning-tree algorithm in a switched LAN?
A. To provide a monitoring mechanism for networks in switched environments.
B. To manage VLANs across multiple switches.
C. To prevent switching loops in networks with redundant switched paths.
D. To segment a network into multiple collision domains.
E. To prevent routing loops in networks.

Back 99

Answer: C
Explanation:
STP is used in LANs with redundant paths or routes to prevent loops in a layer 2
switched or bridged LAN.

Hint 99

Incorrect Answers:
A, B: The primary purpose of STP is to prevent loops, not for monitoring or management
of switches or VLANs.
D. VLANs are used to segment a LAN into multiple collision domains, but the STP
process alone does not do this.
E. Routers are used to prevent routing loops at layer 3 of the OSI model. STP operates at
layer 2.

Front 100

Which two of the following values does STP take into consideration when it elects
the root bridge? (Select two answer choices)
A. The BPDU version number
B. The access layer bridge setting
C. The Bridge ID
D. The spanning-tree update number
E. The bridge priority
F. The VLAN number

Back 100

Answer: C, E
Explanation:
The bridges elect a root bridge based on the bridge IDs in the BPDUs. The root bridge is
the bridge with the lowest numeric value for the bridge ID. Because the two part bridge
ID starts with the priority value, essentially the bridge with the lowest priority becomes
the root. For instance, if one bridge has priority 100, and another bridge has priority 200,
the bridge with priority 100 wins, regardless of what MAC address was used to create the
bridge ID or each bridge/switch.

Hint 100

Reference: CCNA Self-Study CCNA ICND Exam Certification Guide (Cisco Press,
ISBN 1-58720-083-X) Page 39

Front 101

Which of the following are spanning tree port states? (Select three answer choices)
A. Learning
B. Spanning
C. Listening
D. Forwarding
E. Initializing
F. Filtering
G. Permitting

Back 101

Answer: A, C, D
Explanation:
There are 4 STP states that a bridge port can be in: Blocking, Listening, Learning, and Forwarding

Front 102

What are the switch and bridge port characteristics of a layer two spanning-tree
network that is fully converged?
A. All switch and bridge ports are in the forwarding state.
B. All switch and bridge ports are in the stand-by state.
C. All switch and bridge ports are assigned as either root or designated ports.
D. All switch and bridge ports are in either the forwarding or blocking state.
E. All switch and bridge are either blocking or looping.

Back 102

Answer: D
Explanation:
When a switch first comes up, it will be in the listening and learning states. This is
needed so that the switch learns the MAC addresses of the devices on the LAN, and to
learn where any loops in the network may exist. After this initial period of listening and
learning, the ports will be forwarding to the hosts, or blocking certain ports that create a
loop in the network.
An example of this is shown below:
In the above figure, after the network has converged, spanning tree protocol puts each
port either in designated (Forwarding) or Non-designated (Blocking) state. So, Choice D
is correct.
If you get a converged spanning-tree network, you have only two port states.
Forwarding and Blocking. Forwarding: all traffic will be forwarded
Blocking: all traffic to devices that will create a loop in a spanning-tree network will be
blocked. It is possible to get redundant paths in large switched and routed networks.

Front 103

In a switched LAN network, what is the Spanning-Tree algorithm used for?
A. It is used to provide a mechanism for routing updates in switched environments.
B. It is used to prevent routing loops in networks with redundant routes.
C. It is used to prevent switching loops in networks with redundant switched routes.
D. It is used to manage, the addition, deletion, and naming of VLANs across multiple
switches.
E. It is used to segment a network into multiple collision domains.
F. None of the above.
G. All of the above are functions of STP.

Back 103

Answer: C
Explanation:
To avoid loops, all bridging devices, including switches, use STP. STP causes each
interface on a bridging device to settle into a blocking state or a forwarding state.
Blocking means that the interface cannot forward or receive data frames. Forwarding
means that the interface can send and receive data frames. By having a correct subset of
the interfaces blocked, a single currently active logical path will exist between each pair
of LANs. STP resides at the data link layer, so it is used to prevent loops within a
switched network. It is not used to prevent routing loops; that is the function of the
mechanisms within a routing protocol.

Hint 103

Reference:
CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press, ISBN
1-58720-094-5) page 248.

Front 104

In which Spanning-Tree states does a switch port learn MAC addresses? (Select
two)
A. Blocking
B. Listening
C. Forwarding
D. Learning
E. Relaying

Back 104

Answer: C, D
Explanation:
STP uses a couple of port states besides forwarding and blocking.
1. Listening - Listens to incoming Hello messages to ensure that there are no loops, but
does not forward traffic. This is an interim state between blocking and forwarding.
2. Learning - Still listens to BPDUs, plus learns MAC addresses from incoming frames. It
does not forward traffic. This is an interim state between blocking and forwarding.
3. Disabled - Administratively down.

Hint 104

Reference: Cisco CCNA intro 640-821

Front 105

When is a switched network that is running the Spanning Tree Protocol considered
to be fully converged?
A. when all switches have the same BID as the root switch
B. when all switches have received the MAC address of each neighboring switch
C. when every enabled switch port has been assigned a unique identifier
D. when every operating switch port is in either the blocking or forwarding state
E. when all switches are in either client, server, or transparent mode

Back 105

Answer: D
Explanation:
States of the Spanning Tree Protocol:
Blocking A blocked port won't forward frames; it just listens to BPDUs. All ports are in
blocking state by default when the switch is powered up. The purpose of the blocking
state is to prevent the use of looped paths.
Listening The port listens to BPDUs to make sure no loops occur on the network before
passing data frames. A port in listening state prepares to forward data frames without
populating the MAC address table.
Learning The switch port listens to BPDUs and learns all the paths in the switched
network. A port in learning state populates the MAC address table but doesn't forward
data frames.
Forwarding The port sends and receives all data frames on the bridged port.
Disabled A port in the disabled state does not participate in the frame forwarding or STP.
A port in the disabled state is virtually non-operational.
In Blocking States, all ports are in blocking state. The purpose of the blocking state is to
prevent the use of looped paths. The forward state sends and receives the all data frames
in a loop free network. So these two states are considered to be fully converged.

Front 106

What is the purpose of the Spanning Tree Protocol (STP)?
A. To prevent routing loops
B. To create a default route
C. To provide multiple gateways for hosts
D. To maintain a loop-free Layer 2 network topology
E. To enhance the functions of SNMP

Back 106

Answer: D
Explanation:
STP's main task is to stop network loops from occurring on your Layer 2 network
(bridges or switches). It vigilantly monitors the network to find all links, making sure that
no loops occur by shutting down any redundant ones. STP uses the spanning-tree
algorithm (STA) to first create a topology database, then search out and destroy
redundant links. With STP running, frames will only be forwarded on the premium,
STP-picked links.

Front 107

Which of the following components must be elected before the Spanning Tree
Protocol can converge in a switched LAN?
A. Designated ports.
B. Duplex operating mode.
C. Fast mode ports.
D. Root bridge.
E. Root ports.
F. BDPU priority.

Back 107

Answer: A, D, E
Explanation:
Designated port: Either a root port or a port that has been determined as having the best (lower) cost-a
designated port will be marked as a forwarding port.
Root bridge: The root bridge is the bridge with the best bridge ID. With STP, the key is for all the switches
in the network to elect a root bridge that becomes the focal point in the network. All other decisions in the
network-like which port is to be blocked and which port is to be put in forwarding mode-are made from the
perspective of this root bridge.
Root port: Always the link directly connected to the root bridge, or the shortest path to the root bridge. If
more than one link connects to the root bridge, then a port cost is determined by checking the bandwidth of
each link. The lowest cost port becomes the root port.
So these three components must be elected before the spanning tree protocol can
converge in a switched LAN

Front 108

Why would the Certkiller administrator change the value of the spanning-tree
priority of a switch?
A. in order to optimize the path that frames take from source to destination
B. to increase the priority so a designated port will become a root port
C. to increase the BID, so the switch is more likely to become root bridge
D. in order to allow VLANs to be sent from one switch to another across a single link
E. to force a given switch to become an STP server
F. None of the above

Back 108

Answer: A
Explanation:
The Bridge Priority is used to measure the preference of a bridge in the spanning-tree
Algorithm. The possible values range between 0 and 65,535. The default setting is
32,768. By adjusting the priority, the root bridge can be manually assigned to meet the
needs of the network administrator.

Front 109

What value is primarily used to determine which port becomes the root port on
each nonroot switch in a spanning-tree topology?
A. path cost
B. lowest port MAC address
C. VTP revision number
D. highest port priority number
E. port priority number and MAC address
F. None of the above

Back 109

Answer: A
Explanation:
At the conclusion of the root bridge election process, the switches move on to selecting
Root Ports. The Root Port of a bridge is the port that is closest to the Root Bridge in
terms of Path Cost. Every non-Root Bridge must select one Root Port. Again, bridges use
the concept of cost to measure closeness. As with some routing metrics, the measure of
closeness using STP is not necessarily reflected by hop count. Specifically, bridges track
what is referred to as Root Path Cost, which is the cumulative cost of all links to the Root
Bridge.

Front 110

In the Certkiller switched LAN environment, what does the IEEE 802.1Q standard
describe?
A. VLAN pruning
B. A method of VLAN trunking
C. An approach to wireless LAN communication
D. The operation of VTP
E. The process for root bridge selection
F. None of the above

Back 110

Answer: B
Explanation:
A broadcast domain must sometimes exist on more than one switch in the network. To
accomplish this, one switch must send frames to another switch and indicate which
VLAN a particular frame belongs to. On Cisco switches, a trunk link is created to
accomplish this VLAN identification. ISL and IEEE 802.1Q are different methods of
putting a VLAN identifier in a Layer 2 frame.
The IEEE 802.1Q protocol interconnects VLANs between multiple switches, routers, and
servers. With 802.1Q, a network administrator can define a VLAN topology to span
multiple physical devices.
Cisco switches support IEEE 802.1Q for FastEthernet and Gigabit Ethernet interfaces.
An 802.1Q trunk link provides VLAN identification by adding a 4-byte tag to an
Ethernet Frame as it leaves a trunk port.

Front 111

You are an administrator of the Certkiller switched network and your goal is to
reduce some of the administrative overhead on your network. You plan on
achieving this by configuring a new VLAN for each department in the Certkiller
network. However, you need to share the VLAN information across numerous
switches. Which of the following would allow you accomplish this?
A. STP
B. GVRP
C. SNMP
D. VTP
E. DHCP
F. None of the above

Back 111

Answer: D
Explanation:
The VTP (VLAN Trunking Protocol) is a Cisco Layer 2 messaging protocol that
manages the addition, deletion, and renaming of VLANs on a network-wide basis. It
allows for VLAN information to span multiple switches within the switch domain.

Hint 111

Incorrect Answers:
A. STP is a switching protocol but it is used for preventing network loops.
B. GVARP is an actual protocol used in switch administration, but it beyond the scope of
what a CCNA is expected to know.
C. SNMP is a protocol used for managing and monitoring networks
E. DHCP is the Dynamic Host Configuration Protocol, which allows for PC's to obtain
their IP address dynamically upon booting up, along with their DNS and default gateway
information.

Front 112

Which of the following a true statements regarding the use of VLANs to segment a
network? (Select three)
A. They increase the size of collision domains
B. They allow logical grouping of users by function.
C. They can enhance network security.
D. They increase the size of the broadcast domain while decreasing the number of
collision domains.
E. They increase the number of broadcast domains while decreasing the size of the
broadcast domains.
F. They simplify switch administration.

Back 112

Answer: B, C, E
Explanation:
VLANs are used to segment a LAN into multiple, smaller LANs. This can be used to
enhance security as local traffic from one VLAN will not be passed to users in other
VLANS.

Hint 112

Incorrect Answers:
A. VLANs are used to decrease the size of a collision domain, not increase it.
D. The opposite is true.
F. The default operation of a switch is to allow all traffic and to enable all ports in VLAN
1. The use of VLANs will increase the complexity of the switch environment, making for
more difficult administration.

Front 113

You wish to segment your LAN into multiple broadcast domains. Which technology
method should you implement in order to do this?
A. Transparent bridging
B. Cut-through switching
C. Fragment-free switches
D. Virtual LANs
E. Store-and-forward switching
F. None of the above

Back 113

Answer: D
Explanation:
The creation of VLANs in a switch will provide separate Broadcast domains. By default,
all ports in a Catalyst switch belong to VLAN 1. By creating additional VLANs, the
LAN will be logically segmented into separate broadcast domains.

Hint 113

Incorrect Answers
A. Transparent bridging is called Transparent because the endpoints devices do not need
to know that the bridges exists. It will not play any role for creating separate broadcast
domain
B, E. Both of these are switching methods.
C. This has nothing to do with the creation of multiple broadcast domains.

Front 114

Certkiller has implemented the use of VLANs in their network. Which of the
following are considered to be a benefit of VLANs? (Choose three)
A. They increase the size of collision domains.
B. They allow logical grouping of users by function.
C. They can enhance network security,
D. The increase the size of broadcast domains while decreasing the number of the
broadcast domains.
E. The increase the number of broadcast domains while decreasing the size of the
broadcast domains.
F. They simplify switch administration.

Back 114

Answer: B, C, E
Explanation:
There are many motivations for using VLANs, including these:
1. To group users by department, or by groups that work together, instead of by physical
location. (B)
2. To reduce overhead by limiting the size of each broadcast domain (E)
3. To enforce better security by keeping sensitive devices on a separate VLAN (C)
4. To separate specialized traffic from mainstream traffic - for example, putting IP
telephones on a separate VLAN form user PCs.

Front 115

What are some of the characteristics of a typical VLAN arrangement, found
throughout the Certkiller switched LAN? (Select all that apply)
A. VLANs logically divide a switch into multiple, independent switches at Layer 2.
B. Trunk links can carry traffic for multiple VLANs.
C. VLAN implementation significantly increases traffic due to added trunking
information.
D. A VLAN can span multiple switches.
E. VLANs typically increase the number of switches needed
F. VLANs typically decrease the number of switches needed

Back 115

Answer: A, B, D
Explanation:
VLANs give you the power of making virtual LAN networks to subdivide collision
domains into smaller units of functionality, without being limited by physical location.
A is correct because that is the exact function of a VLAN. B is correct because trunk
links are used to carry traffic for multiple VLANs. D is correct because a VLAN can and
often does span across multiple switches. VTP makes this possible.

Hint 115

Incorrect Answers:
C. Although trunking information does indeed add some level of overhead, the overall
traffic overhead is greatly reduced though the use of VLANs.
E, F. The number of total switches needed in a network is the result of the number of
devices on the entire LAN that need to be connected. Whether VLANs are used or not
will have little, if any, impact on the total number of switches needed in a LAN.

Front 116

How could the Certkiller corporation benefit from using VLANs on their network?
(Select three answer choices.)
A. VLANs allow access to network services based on department, not physical location.
B. VLANs utilize packet filtering to enhance network security.
C. VLANs provide a low-latency, high bandwidth internetworking alternative.
D. VLANs provide a method of communication between IP addresses in large networks.
E. VLANs establish segmented broadcast domains in switched networks.
F. VLANs can greatly simplify adding, moving, or changing hosts on the network.

Back 116

Answer: A, E, F
Explanation:
VLANs establish broadcast domains in switched networks, so by virtue of having the
option to create many efficient broadcast domains, congestion is reduced and network
throughput is greatly enhanced. VLANs allow networks to be divided by department or
resource needs, rather then by physical location. When people move departments, leave a
department, or join a department, administration is easy and convenient with a few
keystrokes.

Hint 116

Incorrect Answers:
B, D. These would be router functions at layer 3. Switches and VLANs operate at layer 2
of the OSI model.
C. The use of VLANs may actually increase the latency in some cases, as traffic from
one VLAN to the other will need to be routed.

Front 117

You are working as a network technician at Certkiller University, when you get a
call from the Engineering Faculty. They're complaining that they're receiving
obsolete information from the Business Faculty's network traffic broadcasts.
What can you do to contain the Business Faculty's broadcast while still keeping it
connected to the internet and the enterprise services of the University? (Select all
valid answer choices)
A. Use half and full-duplex Ethernet on the Engineering Department LAN
B. Establish a VTP domain to minimize the obsolete traffic
C. Change the switch IP address of the switch
D. Create separate VLANs and subnets for the two departments and route between the
two
E. Provide greater bandwidth to the Engineering Department LAN
F. Place the business department on a separate subnet and route between networks

Back 117

Answer: D, F
Explanation:
In order to prevent the broadcast and link level multicast traffic separated between the
departments, they need to be isolated at layer two. This can be accomplished in two
ways. The first is to create separate VLANs and place each department into a different
one. The second method would be to separate the two departments into two completely
different networks, and route between them.

Hint 117

Incorrect Answers:
A. Mixing the use of half and full duplex will make no difference to the number of
broadcasts sent.
B. Trunking is only useful in networks that already contain VLANs.
C. This will make no difference, as all users will still be contained within the same IP
subnet.
E. The amount of bandwidth involved will not have any impact on the amount of
broadcasts that are sent and received.

Front 118

Which of the following steps are necessary in order to add a new VLAN to the
Certkiller switched network? (Select all that apply)
A. Create the VLAN.
B. Name the VLAN.
C. Configure an IP address for the VLAN.
D. Add the desired ports to the new VLAN.
E. Add the VLAN to the VTP domain.

Back 118

Answer: A, B, D
Explanation:
The following are the basic requirements for creating VLANs:
* Creating the VLAN numbers and names
* Configuring each port's assigned VLAN

Hint 118

Incorrect Answers:
C. This is an optional feature, but not a necessary step for creating a VLAN.
E. Adding any VLAN to a Virtual Trunking Protocol (VTP) domain may be desired in a
complex multi-switch and multi-VLAN network. However, it is not a necessary step for
creating stand-alone VLANs on a single switch.

Front 119

You need to create a new VLAN on your Catalyst switch. This VLAN is to be named
Certkiller . Which of the following need to be completed for the creation of this
new VLAN? (Select all that apply)
A. The Certkiller VLAN must be created.
B. The desired ports must be added to the new Certkiller VLAN.
C. The Certkiller VLAN must be added to all of the domains.
D. The Certkiller VLAN must be named.
E. An IP address must be configured for the Certkiller VLAN.
F. None of the above. VLAN creations are automatic.

Back 119

Answer: A, B, D
Explanation:
Creating a VLAN is done in 3 steps:
1. Create the VLAN
2. Name the VLAN
3. Assign ports to the VLAN
From there, other features and functionality can be configured, but these are the only
steps that are required for the addition of a VLAN.

Hint 119

Incorrect Answers:
C. The VLAN needs only to be added to a single switch, where it can act as a stand-alone
VLAN, or it can be transferred to other switches in the network through the use of the
VTP protocol.
E. VLANs operate at layer 2, and although many are configured with a layer 3 IP
address, it is not absolutely necessary to do this.

Front 120

What must the Certkiller network administrator do in order to successfully
configure VTP so that VLAN information can be propagated across the trunk
between two switches named CK1 and CK2 ? (Select two answer choices)
A. Set each end of the trunk link to IEEE 802.1Q encapsulation.
B. Set the same VTP management domain name on both switches.
C. Set all ports on the two switched as access ports.
D. Configure one of the two switches as a VTP server.
E. Connect the two switches using a rollover cable.
F. Use a router to forward VTP traffic between the VLANs.

Back 120

Answer: B, D
Explanation:
All switches that need to share VLAN information via a trunk must use the same VTP
domain name, and a switch can only be in one domain at a time. This means that a switch
can only share VTP domain information with other switches if they're configured into the
same VTP domain. You can use a VTP domain if you have more than one switch
connected in a network, but if you've got all your switches in only one VLAN, you don't
need to use VTP. VTP information is sent between switches via a trunk port.
Switches advertise VTP management domain information, as well as a configuration
revision number and all known VLANs with any specific parameters. There's also
something called VTP transparent mode, in it, you can configure switches to forward
VTP information through trunk ports, but not to accept information updates or update
their VTP databases. At least one of the switches will need to be configured as the VTP
server in order to pass the VLAN info.

Hint 120

Incorrect Answers:
A. Although this is a valid option, it is not a requirement since using ISL as the
encapsulation type is also a valid option.
E. A rollover cable is not used between switches for any of the port types.
F. Routers will be required for sending traffic from one VLAN to the other, but not to
forward the actual VTP traffic.

Front 121

After connecting a PC to an available port on a switch, you find that the PC can not
access any of the resources on the LAN. No other PC's connected to the switch
appear to be having any issues. What is the most likely cause for this problem?
A. The router lacks a routing table entry for the new host
B. The host switch port is assigned to the incorrect VLAN
C. The host MAC address is incorrectly configured
D. A STP instance for the new host has not been initialized
E. The switch does not have the MAC address hard coded in the CAM table.

Back 121

Answer: B
Explanation:
Virtual LANs break up broadcast domains in a layer-two switched internetwork. If a host
is in a different VLAN then the network services it needs to use, the packets must go
through a router. If routing does not take place, the PC will be unable to communicate
with any other devices not in the same VLAN. Answer B is the best answer for this
question.

Hint 121

Incorrect Answers:
A. The PC is unable to communicate with other LAN users. No router needs to even be
installed for this to work.
C, E. The MAC address of the PC does not need to be entered manually into the switch. The switch will dynamically learn of the MAC address of the PC.
D. The STP algorithm does not need to have any end host information added in order for
it to work.

Front 122

The Certkiller network administrator needs to verify that switch interface 0/5 has
been assigned to the Marketing VLA.N. Which command will accomplish this task?
A. Show vlan
B. Show mac-address-table
C. Show vtp status
D. show spanning-tree root
E. show ip interface brief
F. None of the above

Back 122

Answer: A
Explanation:
The "show vlan" command displays the configured vlan name and ID as well as the ports
that belong to each VLAN, etc. By default all ports belongs to VLAN 1
Note: You can also use: show vlan brief, show vlan ID where ID is the VLAN ID.

Front 123

A new trunk has been configured on a switch in the Certkiller LAN. By default,
which VLANs are allowed over this trunk link?
A. No VLANs
B. Only the VLANs that are specified when creating the trunk
C. Only VLANs 1-64
D. All VLANs
E. All VLAN's except VLAN 1
F. None of the above

Back 123

Answer: D
Explanation:
Trunk ports send and receive information from all VLANs by default, and if a frame is
untagged, it's sent to the management VLAN. This applies to the extended range VLANs
as well. But we can remove VLANs from the allowed list to prevent traffic from certain
VLANs from traversing a trunked link.
Here is example:
RouterA(config)#int f0/1
RouterA(config-if)# switchport mode trunk
RouterA(config-if)#switchport trunk allowed vlan VLANID
RouterA(config-if)#switchport trunk allowed vlan remove VLANID

Front 124

The Certkiller network administrator has just issued the "switchport trunk native
vlan 998" command on switch CK2 . What is the function of this command?
A. It designates VLAN 998 as the default for all unknown tagged traffic
B. It designates VLAN 998 for untagged traffic
C. It blocks VLAN 998 traffic from passing on the trunk
D. It creates a VLAN 998 interface
E. None of the above

Back 124

Answer: B
Explanation:
Native VLAN is the VLAN that you configure on the Catalyst interface before you
configure the trunking on that interface. By default, all interfaces are in VLAN 1.
Therefore, VLAN 1 is the native VLAN that you can change. On an 802.1Q trunk, all
VLAN packets except the native VLAN are tagged. You must configure the native
VLAN in the same way on each side of the trunk. Then, the router or switch can
recognize to which VLAN a frame belongs when the router or switch receives a frame
with no tag.
To configure the native VLAN use the following command.
Cat2950(config-if)# switchport trunk native vlan 10

Front 125

You are bringing up a new Certkiller switch, and wish to connect it via a trunk to
another switch from a different vendor, which uses the IEEE standard for the
trunking method. When setting the encapsulation type on the trunk, what should
you configure on the Cisco switch?
A. Switch(config)# switchport trunk encapsulation isl
B. Switch(config)# switchport trunk encapsulation ietf
C. Switch(config-if)# switchport trunk encapsulation isl
D. Switch(config-if)# switchport trunk encapsulation ietf
E. Switch(config-if)# switchport trunk encapsulation dot1q

Back 125

Answer: E
Explanation:
The only real choices for setting up switching trunks are ISL and 802.1Q. ISL is Cisco
proprietary, while 802.1Q uses the IEEE defined standard for trunking between switches.
To configure the 802.1Q standard, the keyword "dot1q" is used in Cisco switches.

Hint 125

Incorrect Answers:
A, B, D. These are not valid options in a Cisco switch.
C. ISL is a Cisco proprietary method for setting up trunks, and will only work between
Cisco switches.

Front 126

A new switch is being installed in the Certkiller network and you have been assigned
the task of connecting it to an existing switch. In doing this, you want to set up the
VLAN Trunking Protocol so that VLAN information can be passed between the
switches. Which of the following must you do to accomplish this? (Choose all that
apply).
A. You must set each end of the trunk line to IEEE 802.1e encapsulation.
B. You must set the same VTP management domain name on both switches.
C. You must set all ports on the two switches as access ports.
D. You must configure one of the switches as a VTP server.
E. You must use a rollover cable to connect the two switches.

Back 126

Answer: B, D
Explanation:
The following describes what is needed in order to correctly set up VTP:
VTP operates in one of three modes:
* Server mode
* Client mode
* Transparent mode
For VTP to exchange information, some switches act as servers, and some act as clients. VTP servers can create, modify, and delete VLANs and other configuration parameters for the entire VTP domain; this information, in turn, is propagated to the VTP clients and servers in that same domain. VTP servers save VLAN configurations in the Catalyst NVRAM, whereas in clients, the VLAN configuration is not stored at all. A VTP client cannot create, change, or delete VLANs, nor can it save VLAN configurations in nonvolatile memory.

Hint 126

Incorrect Answers:
A. The encapsulation can be either ISL or 802.1Q, and need to match at each end of the
trunk.
C. Ports must only be assigned to VLANS. Once that is done and the trunk is up and
running, the VLAN information will be passed between the switches.
E. A regular CAT5 cable is used to connect the switches, assuming 10/100 Ethernet is
used.

Front 127

A new Certkiller switch is installed into an existing LAN and a new VTP trunk is set
up with an existing switch. Which VLANs will be allowed on this new trunk?
A. All defined VLANs are allowed on the trunk by default.
B. Each VLAN, or VLAN range, that is specified with the switchport mode command.
C. Each VLAN, or VLAN range, that is specified with the vtp domain command.
D. Each VLAN, or VLAN range, that is specified with the vlan database command.
E. None of the above

Back 127

Answer: A
Explanation:
The question does not state that there are multiple VTP Domains meaning that all defined
VLANs are allowed on the trunk until a vtp domain command is issued.

Front 128

You need to decide on which trunking method to implement in the Certkiller
network. What is a characteristic of ISL and 802.1q frame tagging in a switched LAN environment?
A. They are used to find the best path through a network.
B. They allow the exchange of filtering tables.
C. They specify different implementations of the Spanning-Tree Protocol.
D. They allow the exchange of routing tables
E. They provide inter-switch VLAN communication.

Back 128

Answer: E
Explanation: A trunk link is the other type of Layer 2 port supported on Cisco
switches. When a trunk port is configured, it begins marking frames as they
exit the port to indicate which VLAN each frame is associated with. The
trunk port can also read the markings, called tags, as they enter the trunk
port. This enables the switch to send a frame only to the ports for the
given VLAN associated with the incoming frame.
The main purpose of trunking is to carry traffic between switches and
maintain the VLAN information. Unlike an access link, the trunk link does
not belong to a single VLAN but instead can carry traffic from several VLANs
over a point-to-point link between two devices that understand the protocol.
Two forms of trunking are used for Cisco switches on Ethernet networks:
An IEEE industry standard called IEEE 802.1Q. This is a frame-tagging
mechanism that adds a VLAN identifier to the frame by inserting a tag at
Layer 2.
Another form of trunking on Cisco switches is called Inter-Switch Link
(ISL), which is a Cisco proprietary trunking mechanism. ISL uses a frame
encapsulation method that adds a header to identify the VLAN.

Hint 128

Incorrect Answers:
A, D. These are the functions of routers, not switches.
B. Filtering tables can be used on certain Catalyst switches via the use of VLAN access
control lists, but this information is never shared between switches.
C. A separate STP instance is created for each VLAN, but the STP implementation
remains the same.

Front 129

Which one of the following protocols allows the information about the configuration
of a new VLAN to be distributed across entire switched network?
A. STP
B. VTP
C. EIGRP
D. SNMP
E. CDP
F. None of the above

Back 129

Answer: B
Explanation:
Sybex CCNA Study Guide 4th Edition states on page 359:
"The basic goals of VLAN Trunking Protocol (VTP) are to manage all configured
VLANs across a switched internetwork and to maintain consistency throughout that
network. VTP allows an administrator to add, delete, and rename VLANs-information
that is then propagated to all other switches in the VTP domain."

Hint 129

Incorrect Answers:
A. STP is the Spanning Tree Protocol, used to prevent bridging loops in a LAN.
C. EIGRP is a routing protocol used to exchange routing information, not VLAN
information.
D. SNMP is the Simple Network Management Protocol, used to provide information to
remote network management stations.
E. CDP is the Cisco Discovery Protocol, which is used to exchange information between
Cisco devices. It can only be used between Cisco routers and switches.

Front 130

Which encapsulation types are configurable on a Cisco switch for a trunk? (Select
two answer choices)
A. VTP
B. ISL
C. CDP
D. 802.1Q
E. 802.1p
F. LLC
G. IETF

Back 130

Answer: B, D
Explanation:
Trunks are used to carry traffic belonging to multiple VLANs between devices over the
same link. A device can determine which VLAN the traffic belongs to by its VLAN
identifier. The VLAN identifier is a tag that is encapsulated with the data. ISL and 802.1q
are two types of encapsulations used to carry data from multiple VLANs over trunk links.
ISL is a Cisco proprietary protocol for interconnecting multiple switches and maintaining
VLAN information as traffic goes between switches. ISL provides VLAN trunking
capabilities while maintaining full wire speed performance on Ethernet links in
full-duplex or half-duplex mode. ISL operates in a point-to-point environment and will
support up to 1000 VLANs. In ISL, the original frame is encapsulated and an additional header is added before the frame is carried over a trunk link. At the receiving end, the
header is removed and the frame is forwarded to the assigned VLAN. .ISL uses Per
VLAN Spanning Tree (PVST) which runs one instance of Spanning Tree Protocol (STP)
per VLAN. PVST allows for optimal root switch placement for each VLAN and supports
load balancing of VLANs over multiple trunk links.
802.1Q is the IEEE standard for tagging frames on a trunk and supports up to 4096
VLANs. In 802.1Q, the trunking device inserts a four-byte tag into the original frame and
re-computes the Frame Check Sequence (FCS) before sending the frame over the trunk
link. At the receiving end, the tag is removed and the frame is forwarded to the assigned
VLAN. 802.1Q does not tag frames on the native VLAN. It tags all other frames
transmitted and received on the trunk. While configuring a 802.1 trunk, you must make
sure that the same native VLAN is configured on both sides of the trunk. IEEE 802.1Q
defines a single instance of spanning tree running on the native VLAN for all the VLANs
in the network which is called Mono Spanning Tree (MST). This lacks the flexibility and
load balancing capability of PVST available with ISL. However, PVST+ offers the
capability to retain multiple Spanning Tree topologies with 802.1Q trunking.

Front 131

You need to configure an 802.1Q link on a Certkiller switch. Which commands,
when used together, would do this? (Select two answer choices)
A. Switch(vlan)# mode trunk
B. Switch(config)# switchport access mode trunk
C. Switch(config-if)# switchport mode trunk
D. Switch(config-if)# switchport trunk encapsulation dot1q
E. Switch(config)# switchport access mode 1
F. Switch(vlan)# trunk encapsulation dot1q

Back 131

Answer: C, D
Explanation:
Creating this trunk link is a two step process. First you have to set the switchport mode to
trunk, and then you configure the encapsulation. The giveaway on this question is the
fact that to create a trunk on an interface, you have to be in interface configuration mode.
So switchport mode trunk sets the trunk, and switchport trunk encapsulation dot1q sets
the encapsulation.

Front 132

Which of the following are VLAN frame encapsulation types that may be
configured on a Catalyst switch? (Choose two.)
A. VTP
B. ISL
C. CDP
D. 802.1Q
E. 802.1p
F. LLC

Back 132

Answer: B, D
Explanation:
The two VLAN trunking encapsulation types are:
Inter-Switch Link (ISL): This is proprietary to Cisco switches, and it's used for Fast
Ethernet and Gigabit Ethernet links only. ISL routing can be used on a switch port, router
interfaces, and server interface cards to trunk a server. ISL lets you explicitly tag VLAN
information onto an Ethernet frame. This tagging information allows VLANs to be
multiplexed over a trunk link through an external encapsulation method, which allows
the switch to identify the VLAN membership of a frame over the trunked link.
IEEE 802.1Q: Created by the IEEE as a standard method of frame tagging, this actually
inserts a field into the frame to identify the VLAN. If you're trunking between a Cisco
switched link and a different brand of switch, you have to use 802.1Q for the trunk to
work.

Front 133

There are 2 switches in the Certkiller LAN, with no routers. Ports 1, 2 & 3 are
assigned to VLAN 1 in switch 1 and 2 and ports 4, 5 & 6 are assigned to VLAN 2 in
both switches. These two switches are connected together via a trunked link. Which
of the conditions below would verify trunk and VLAN operation? (Select all valid
answers)
A. Host 1 on VLAN 1 can ping Host 2 on VLAN 1
B. Host 1 on VLAN 1 can ping Host 4 on VLAN 2
C. Host 1 on VLAN 1 can not ping Host 2 on VLAN 1
D. Host 4 on VLAN 2 can not ping Host 1 on VLAN 1
E. Host 4 on VLAN 2 can ping Host 2 on VLAN 2

Back 133

Answer: A, D, E
Explanation:
If there is no router present, only hosts in the same VLAN will be able to ping each other.
In order for any host on one VLAN to communicate with a host on another VLAN, the
traffic must pass through a router. Host within the same VLAN will be able to ping each
other, even though they reside on different switches, as long as the switches have a trunk
connection configured between them.

Front 134

The Certkiller network administrator has issued the "VTP password Certkiller "
command on a Cisco device. What is the purpose of this command?
A. It allows two VTP servers to exists in the same domain, each configured with different
passwords
B. It is the password required when promoting a switch from VTP client mode to VTP
server mode
C. It is used to access the VTP server to make changes to the VTP configuration
D. It is used to validate the sources of VTP advertisements sent between switches
E. None of the above

Back 134

Answer: D
Explanation:
When you create the VTP domain, you have a bunch of options, including setting the
domain name, password, operating mode, and pruning capabilities of the switch. Use the
vtp global configuration mode command to set all this information.
The purpose of setting password on VTP is to validate the sources of VTP advertisements
sent between switches belonging to same VTP domain.

Front 135

Which VTP mode should a Cisco switch be set to if this switch is to add or delete
VLANs to a management domain?
A. Transparent
B. Server
C. Auto
D. Client
E. User

Back 135

Answer: B
Explanation:
VTP Modes:
If you intend to make a switch part of a VTP management domain, each switch must be
configured in one of three possible VTP modes. The VTP mode assigned to a switch will
determine how the switch interacts with other VTP switches in the management domain.
The three VTP modes that can be assigned to a Cisco switch include server mode, client
mode, and transparent mode. Each of these roles is outlined below:
Server Mode Once VTP is configured on a Cisco switch, the default mode used is Server
Mode. In any given VTP management domain, at least one switch must be in Server
Mode. When in Server Mode, a switch can be used to add, delete, and modify VLANs,
and this information will be passed to all other switches in the VTP management domain. Client Mode When a switch is configured to use VTP Client Mode, it is simply the
recipient of any VLANs added, deleted, or modified by a switch in Server Mode within
the same management domain. A switch in VTP client mode cannot make any changes to
VLAN information.
Transparent Mode A switch in VTP Transparent Mode will pass VTP updates received
by switches in Server Mode to other switches in the VTP management domain, but will
not actually process the contents of these messages. When individual VLANs are added,
deleted, or modified on a switch running in transparent mode, the changes are local to
that particular switch only, and are not passed to other switches in the VTP management
domain.
Based on the roles of each VTP mode, the use of each should be more or less obvious.
For example, if you had 15 Cisco switches on your network, you could configure each of
them to be in the same VTP management domain. Although each could theoretically be
left in the default Server Mode, it would probably be easier to leave only one switch in
this configuration, and then configure all remaining switches for VTP Client Mode.
Then, when you need to add, delete, or modify a VLAN, that change can be carried out
on the VTP Server Mode switch and passed to all Client Mode switches automatically. In
cases where you need a switch to act in a relatively standalone manner, or do not want it
to propagate information about its configured VLANs, use Transparent Mode.

Hint 135

Incorrect Answers:
A. A switch in VTP Transparent Mode will pass VTP updates received by switches in
Server Mode to other switches in the VTP management domain, but will not actually
process the contents of these messages.
C, E. These are not valid VTP modes.
D. Client mode merely accepts changes made by the switch that is connected and in
SERVER mode.

Front 136

What are two results of entering the CKSwitch(config)# vtp mode client command
on a Catalyst switch in the Certkiller LAN? (Choose two.)
A. The switch will ignore VTP summary advertisements
B. The switch will forward VTP summary advertisements
C. The switch will process VTP summary advertisements
D. The switch will originate VTP summary advertisements
E. The switch will create, modify and delete VLANs for the entire VTP domain

Back 136

Answer: B, C
Explanation :
Server mode-VTP servers have full control over VLAN creation and modification for
their domains. All VTP information is advertised to other switches in the domain, while
all received VTP information is synchronized with the other switches. By default, a
switch is in VTP server mode. Note that each VTP domain must have at least one server
so that VLANs can be created, modified, or deleted, and VLAN information can be
propagated.
Client mode-VTP clients do not allow the administrator to create, change, or delete any
VLANs. Instead, they listen to VTP advertisements from other switches and modify their
VLAN configurations accordingly. In effect, this is a passive listening mode. Received
VTP information is forwarded out trunk links to neighboring switches in the domain, so
the switch also acts as a VTP relay.
Transparent mode-VTP transparent switches do not participate in VTP. While in
transparent mode, a switch does not advertise its own VLAN configuration, and a switch
does not synchronize its VLAN database with received advertisements. In VTP version 1,
a transparent-mode switch does not even relay VTP information it receives to other
switches, unless its VTP domain names and VTP version numbers match those of the
other switches. In VTP version 2, transparent switches do forward received VTP
advertisements out of their trunk ports, acting as VTP relays. This occurs regardless of
the VTP domain name setting.

Front 137

Study the Exhibit below carefully:
London#show vtp
VTP Version: 2
Configuration Revision: 0
Maximum VLANs supported locally: 64
Number of existing VLANs: 5
VTP Operating Mode: Client
VTP Domain Name: London
VTP Pruning Mode: Disabled
VTP V2 Mode: Disabled
VTP Traps Generation: Disabled
Based on the information given above, what is the VTP function of this particular
switch?
A. Learn and save VTP configuration in the running configuration.
B. Create and change VLANs.
C. Forwards information about VTP configuration.
D. VTP is disabled on this device.
E. VTP is not saved to NVRAM.

Back 137

Answer: C
Explanation:
From the output this switch is operating merely as VTP client, so it basically does as the
VTP server says, and passes on information about VTP configuration to the next switch
in line.

Hint 137

Incorrect Answers:
A. This is incorrect because the function is redundant.
B. This incorrect because the switch must be in server or transparent mode to create and
change VLANs.
D. This is incorrect because if VTP would be disabled, it wouldn't appear on the
command output.
E. If this were true, the VTP configuration information would not be displayed after
being powered on.

Front 138

Certkiller is experiencing network delays. The network administrator discovers that
a worker in a location far from the MDF has connected an old 10BASE-T switch
with redundant links to the existing network. How could this action be responsible
for the impaired network performance?
A. Connecting a host to the old switch has created a broadcast storm.
B. The 10BASE-T switch forced the entire network to be reduced to 10 Mbps operation.
C. The old switch does not support VLANs, which has disabled the VLAN configuration
of the entire the network.
D. The old switch does not support full-duplex operation, effectively forcing half-duplex
operation throughout the network.
E. Spanning Tree Protocol has elected the old switch as the root bridge, creating
inefficient data paths through the switched network.
F. None of the above

Back 138

Answer: E
Explanation:
Without the Spanning Tree Protocol (STP), frames would loop for an indefinite period of time in networks with physically redundant links. To prevent looping frames, STP blocks some ports from forwarding frames so that only one active path exists between any pair of LAN segments (collision domains). The result of STP is good: Frames do not loop infinitely, which makes the LAN usable. However, the network uses some redundant links in case of a failure, but not for balancing traffic. To avoid loops, all bridging devices, including switches, use STP. STP causes each interface on a bridging
device to settle into a blocking state or a forwarding state. Blocking means that the interface cannot forward or receive data frames. Forwarding means that the interface can send and receive data frames. By having a correct subset of the interfaces blocked, a single currently active logical path will exist between each pair of LANs. STP behaves identically for a transparent bridge and a switch. So, the terms bridge, switch, and bridging device all are used interchangeably when discussing STP. Root bridge The root bridge is the bridge with the best bridge ID. With STP, the key is for all the
switches in the network to elect a root bridge that becomes the focal point in the network. All other
decisions in the network-like which port is to be blocked and which port is to be put in forwarding mode-are made from the

Front 139

The Certkiller network administrator wants to ensure that only a single web server
can connect to pot Fa0/1 on a catalyst switch. The server is plugged into the switch's
Fast Eth. 0/1 port and the network administrator is about to bring the server online.
What can the administrator do to ensure that only the MAC address of this server is
allowed by switch port Fa0/1? (Choose two)
A. Configure port Fa0/1 to accept connections only from the static IP address of the
server
B. Configure the MAC address of the server as a static entry associated with port Fa0/1
C. Employ a proprietary connector type on Fa0/1 that is incomputable with other host
connectors
D. Configure port security on Fa0/1 to reject traffic with a source MAC address other
than that of the server
E. Bind the IP address of the server to its MAC address on the switch to prevent other
hosts from spoofing the server IP address

Back 139

Answer: B, D
Explanation:
You can use port security to block input to an Ethernet, Fast Ethernet, or Gigabit Ethernet port when the MAC address of the station attempting to access the port is different from any of the MAC addresses specified for that port. When a secure port receives a packet, the source MAC address of the packet is compared to the list of secure source addresses that were manually configured or autoconfigured (learned) on the port. If a MAC address of a device attached to the port differs from the
list of secure addresses, the port either shuts down permanently (default mode), shuts down for the time you have specified, or drops incoming packets from the insecure host. The port's behavior depends on how you configure it to respond to a security violation.
When a security violation occurs, the Link LED for that port turns orange, and a link-down trap is sent to the Simple Network Management Protocol (SNMP) manager. An SNMP trap is not sent if you configure the port for restrictive violation mode. A trap
is sent only if you configure the port to shut down during a security violation.

Front 140

The network administrator has configured port security on a Certkiller switch. Why
would a network administrator configure port security on this Certkiller device?
A. To prevent unauthorized hosts from getting access to the LAN
B. To limit the number of Layer 2 broadcasts on a particular switch port
C. To prevent unauthorized Telnet or SSH access to a switch port
D. To prevent the IP and MAC address of the switch and associated ports
E. None of the above

Back 140

Answer: A
Explanation:
You can use the port
security feature to restrict input to an interface by limiting and identifying MAC
addresses of the stations allowed to access the port. When you assign secure MAC
addresses to a secure port, the port does not forward packets with source addresses
outside the group of defined addresses. If you limit the number of secure MAC addresses
to one and assign a single secure MAC address, the workstation attached to that port is
assured the full bandwidth of the port.
If a port is configured as a secure port and the maximum number of secure MAC
addresses is reached, when the MAC address of a station attempting to access the port is
different from any of the identified secure MAC addresses, a security violation occurs.
Also, if a station with a secure MAC address configured or learned on one secure port
attempts to access another secure port, a violation is flagged.

Hint 140

Reference:
http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00800d
6

Front 141

The network security policy for Certkiller requires that only one host be permitted to attach dynamically to each switch interface. If that policy is violated, the interface
should be automatically disabled. Which two commands must the Certkiller network
administrator configure on the 2950 Catalyst switch to meet this policy? (Choose
two)
A. SW Certkiller 1(config-if)# switchport port-security maximum 1
B. SW Certkiller 1(config)# mac-address-table secure
C. SW Certkiller 1(config)# access-list 10 permit ip host
D. SW Certkiller 1(config-if)# switchport port-security violation shutdown
E. SW Certkiller 1(config-if)# ip access-group 10

Back 141

Explanation
Catalyst switches offer the port security feature to control port access based on MAC
addresses. To configure port security on an access layer switch port, begin by enabling it
with the following interface configuration command:
Switch(config-if)# switchport port-security
Next, you must identify a set of allowed MAC addresses so that the port can grant them
access. You can explicitly configure addresses or they can be dynamically learned from
port traffic. On each interface that uses port security, specify the maximum number of
MAC addresses that will be allowed access using the following interface configuration
command:
Switch(config-if)# switchport port-security maximum max-addr
Finally, you must define how each interface using port security should react if a MAC
address is in violation by using the following interface configuration command:
Switch(config-if)# switchport port-security violation {shutdown | restrict | protect}
A violation occurs if more than the maximum number of MAC addresses are learned, or
if an unknown (not statically defined) MAC address attempts to transmit on the port. The
switch port takes one of the following configured actions when a violation is detected:
shutdown-The port is immediately put into the errdisable state, which effectively shuts it down. It must
be re-enabled manually or through errdisable recovery to be used again.
restrict-The port is allowed to stay up, but all packets from violating MAC addresses are
dropped. The switch keeps a running count of the number of violating packets and can
send an SNMP trap and a syslog message as an alert of the violation.
protect-The port is allowed to stay up, as in the restrict mode. Although packets from
violating addresses are dropped, no record of the violation is kept.

Front 142

You have configured a Certkiller switch as shown below:
Certkiller 3(config-if)# switchport port-security
Certkiller 3(config-if)# switchport port-security mac-address sticky
Select the action below that results from executing these commands.
A. A dynamically learned MAC address is saved in the VLAN database.
B. A dynamically learned MAC address is saved in the startup-configuration file.
C. Statically configured MAC addresses are saved in the startup-configuration file if
frames from that address are received.
D. A dynamically learned MAC address is saved in the running-configuration file.
E. Statically configured MAC addresses are saved in the running-configuration file if
frames from that address are received.
F. None of the above

Back 142

Answer: D
Explanation:
With port security, the switch supports these types of secure MAC addresses:
Static secure MAC addresses-These are manually configured by using the switchport
port-security mac-address mac-address interface configuration command, stored in the
address table, and added to the switch running configuration.
Dynamic secure MAC addresses-These are dynamically configured, stored only in the
address table, and removed when the switch restarts.
Sticky secure MAC addresses-These are dynamically configured, stored in the address
table, and added to the running configuration. If these addresses are saved in the
configuration file, when the switch restarts, the interface does not need to dynamically
reconfigure them.
You can configure an interface to convert the dynamic MAC addresses to sticky secure
MAC addresses and to add them to the running configuration by enabling sticky learning.
To enable sticky learning, enter the switchport port-security mac-address sticky interface configuration command. When you enter this command, the interface converts all the
dynamic secure MAC addresses, including those that were dynamically learned before
sticky learning was enabled, to sticky secure MAC addresses. The interface adds all the
sticky secure MAC addresses to the running configuration.
The sticky secure MAC addresses do not automatically become part of the configuration
file, which is the startup configuration used each time the switch restarts. If you save the
sticky secure MAC addresses in the configuration file, when the switch restarts, the
interface does not need to relearn these addresses. If you do not save the sticky secure
addresses, they are lost.

Hint 142

Reference:
http://www.cisco.com/en/US/docs/switches/lan/catalyst2950/software/release/12.1_11_ea1/configuration/guide/
s

Front 143

Why would the Certkiller network administrator configure port security on a new
Certkiller switch?
A. To prevent unauthorized Telnet access to a switch port.
B. To limit the number of Layer 2 broadcasts on a particular switch port.
C. To prevent unauthorized hosts from accessing the LAN.
D. To protect the IP and MAC address of the switch and associated ports.
E. To block unauthorized access to the switch management interfaces over common TCP
ports.
F. None of the above

Back 143

Answer: C
Explanation:
You can use the port security feature to restrict input to an interface by limiting and
identifying MAC addresses of the stations allowed to access the port. When you assign
secure MAC addresses to a secure port, the port does not forward packets with source
addresses outside the group of defined addresses. If you limit the number of secure MAC
addresses to one and assign a single secure MAC address, the workstation attached to
that port is assured the full bandwidth of the port.
If a port is configured as a secure port and the maximum number of secure MAC
addresses is reached, when the MAC address of a station attempting to access the port is
different from any of the identified secure MAC addresses, a security violation occurs.
Also, if a station with a secure MAC address configured or learned on one secure port
attempts to access another secure port, a violation is flagged.

Hint 143

Reference:
http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00800d
6

Front 144

Certkiller is using private IP addressing in their network. Which of the following IP
addresses is a private IP address? (Select all that apply)
A. 12.0.0.1
B. 168.172.19.39
C. 172.20.14.36
D. 172.33.194.30
E. 192.168.42.34
F. 11.11.11.1

Back 144

Answer: C, E
Explanation:
Range of IP
Addresses Class of Networks Number of Network
10.0.0.0 to
10.255.255.255.255
A 1
172.16.0.0 to
172.31.255.255
B 16
192.168.0.0 to
192.168.255.255
C 256

Front 145

Certkiller is migrating to a private IP addressing scheme. Which of the following
describe the use of private IP addresses? (Choose two)
A. Addresses chosen by Certkiller .com to communicate with the Internet.
B. Addresses that cannot be routed through the public Internet.
C. Addresses that can be routed through the public Internet.
D. A scheme to conserve public addresses.
E. Addresses licensed to enterprise or ISPs by an Internet registry organization.

Back 145

Answer: B, D
Explanation:
Private IP address space has been allocated via RFC 1918. This means the addresses are
available for any use by anyone and therefore the same private IP addresses can be reused. However they are defined as not routable on the public Internet. They are used
extensively in private networks due to the shortage of publicly registered IP address
space and therefore network address translation is required to connect those networks to
the Internet.