Cs625

Front 1

The OSI network model is considered one of the following.

Back 1

A formal standard.

Front 2

Which of the following application layer protocols are related to electronic mail?

Back 2

SMTP
POP
IMAP

Front 3

Which of the following are disadvantages of an N-Tier architecture over other architectures?

Back 3

Increased load on the network.
Increased management complexity.

Front 4

Consider a circuit whose bandwidth is 16kHz utilizing QAM modulation. Assume the circuit has no noise. What is the resulting data rate (C) of the circuit?

Back 4

64kbps
QAM (Quadrature Amplitude Modulation) involves splitting the symbol into 8 different phases (requiring 3 bits), and two different amplitudes (requiring 1 bit). In total QAM symbol can represent 4 bits. Since the bandwidth is 16kHz, our resulting symbol rate is 16k. The data rate is calculated by multiplying the number of bits per symbol (4 with QAM) by the symbol rate (16k).

Front 5

How much storage space would be required to store 24 hours of audio streamed to a computer at .75x106 bits/sec?

Back 5

8100 Megabytes


.75x106 bits per second is equal to .75Mbps. There are 60 seconds in a minute, 3600 seconds in an hour, and 86,400 seconds in a day. .75Mbps*86,400 seconds = 64,800Megabits. However, the solution is given in Megabytes. So we must divide 64,800 Megabits by 8 bits/byte. Thus, the correct solution is 8100 Megabytes

Front 6

What is the symbol rate of a QAM circuit with a bandwidth of 3000Hz? Assume the circuit has no noise.

Back 6

3000
The symbol rate is usually equal to the bandwidth if there is little or no noise on the circuit. The adjective “QAM” (Quadrature Amplitude Modulation) involves splitting the symbol into 8 different phases (requiring 3 bits), and two different amplitudes (requiring 1 bit). In total QAM symbol can represent 4 bits. However, QAM is only used to calculate the data rate. The symbol rate of the circuit does not change regardless of the modulation used. Thus the symbol rate on this circuit is equal to the bandwidth which is 3000

Front 7

A T1 is a dedicated circuit made up of multiple channels inverse multiplexed together. What is the data transmission rate of one of these channels, assuming that there are no guardbands on the T1 circuit?

Back 7

64Kbps

A T1 is made up of 24 channels that each have a data rate of 64Kbp

Front 8

Suppose you need to send 10Gb/s of data over a distance of 15 miles (between campuses). What type of cable below can support this criterion?

Back 8

Single Mode fiber optic cable

Single mode fiber optic cable is used for long distance transmissions (50 miles or more possible). Multi-mode fiber is often limited to shorter distances (1000 meters or less). Fiber optic cable can support data rates in excess of 10 Gigabits per second. Fiber solutions of 40Gigabits and greater are becoming more common! Coaxial and Category 6 cable cannot transmit data at these high data rates. In addition, Coaxial and Category 6 cable would need some type of repeater solution to transmit over long distances.

Front 9

A digital signal is a rough approximation of its analog counterpart. The difference between a digital signal and its analog counterpart is called the “quantizing error”. Generally, there are two methods to reduce the quantizing error in the digital signal. Select the correct two methods below.

Back 9

Sample the source more frequently (oversampling).

Increase the number of amplitude levels

Sample the source more frequently (oversampling)

Digital signals do not have a phase or amplitude as an analog circuit would. Data compression techniques would only help increase the throughput in a circuit transmitting a circuit. It would not increase the accuracy of the signal sent. One correct choice is to increase the amplitude levels (more steps will minimize the differences between levels) which will lead to a smoother curve. Additionally, if the source circuit is sampled more frequently (often called oversampling), the resulting digital signal will be more accurate with respect to the analog source.

Front 10

It is said the OSI network model suffered from differing philosophies during implementation at the ISO and ITU, and that consequently, the resulting network model became overly complex. From the statements below, select all that correctly explain why the model became complex

Back 10

The OSI model essentially attempted to shoehorn two different architectures into one model.

The OSI model attempted to integrate a “beads on a string” connection based architecture and a connectionless, layer based architecture into one model.

Front 11

Assume you want to assign each of the 300 employees at your organization a unique identification number. Further assume that this number is in binary. Select the minimum number of bits needed for this unique identification number. You do not need to account for future growth of the organization.

Back 11

9 bits.

Front 12

From the alternatives below, select all that represent functions of an application program.

Back 12

Data storage
Presentation logic
Data Access logic
Application logic

Front 13

Does the SMTP standard include the delivery of a message to the receiver's client computer? Why or why not?

Back 13

No, the SMTP standard was developed during the host architecture (mainframe) era. During this period, it made sense for a host to store all received user messages. Users would access their messages via a terminal.

Front 14

atch the layer of the internet model with its function.
Answer
Question Correct Match Selected Match
This layer ensures end to end connections between sender and receiver (including detecting lost messages). In addition, messages are broken up in smaller chunks for ease of transmittal.
B.
Transport Layer
[None Given]
This layer performs routing of messages by selecting the next device a message should be sent to.
E.
Network Layer
[None Given]
This layer is the user’s access to the network. User software encapsulates messages for transfer over the network.
C.
Application Layer
[None Given]
This layer transfers a series of electrical, radio, or light signals through a circuit.
A.
Physical Layer
[None Given]
This layer decides when to transmit messages across the network and formats the start and end of a message. In addition, this layer provides error detection and correction.
D.
Data Link Layer
[None Given]

Back 14

atch the layer of the internet model with its function.
Answer
Question Correct Match Selected Match
This layer ensures end to end connections between sender and receiver (including detecting lost messages). In addition, messages are broken up in smaller chunks for ease of transmittal.
B.
Transport Layer
[None Given]
This layer performs routing of messages by selecting the next device a message should be sent to.
E.
Network Layer
[None Given]
This layer is the user’s access to the network. User software encapsulates messages for transfer over the network.
C.
Application Layer
[None Given]
This layer transfers a series of electrical, radio, or light signals through a circuit.
A.
Physical Layer
[None Given]
This layer decides when to transmit messages across the network and formats the start and end of a message. In addition, this layer provides error detection and correction.
D.
Data Link Layer
[None Given]

Front 15

Review the following scenario, then follow the subsequent instructions.
Company A decides to lease a T3 circuit for its main office. Company A has 4 small sites it wishes to connect to this T3. The circuit provider offers to run 7 T1 lines from each small site to the providers central office. The T1 lines (28 in total) will be combined and passed through the T3 which runs from the provider’s central office to the main office of Company A. At the main office of Company A, a router then processes the incoming T3.
Note that a T3 circuit is composed of multiple T1 circuits. From the alternatives below, select all that correctly describe the process (occurring at the provider's central office) of combining the incoming T1 lines from the small sites to the T3 circuit.

Back 15

Inverse Multiplexing.
BONDING

Front 16

From the alternatives below, select all that are multiplexing standards which use guard bands to separate the various signals operating on the circuit.

Back 16

Frequency Division multiplexing

Front 17

From the alternatives below, select all that are devices or mechanisms which convert analog signals to digital signals.

Back 17

a.
VOIP Telephone

b.
Codec

d.
Software for video, audio, and instant messaging (IM).

e.
Using a sound recording program to create an MP3 file.

Front 18

From the alternatives below, select all that are true of 10 Mbps Ethernet.

Back 18

10Mbps Ethernet uses Manchester encoding.
10Mbps Ethernet uses a bi-polar signaling technique to transmit 1’s and 0’s.
10Mbps Ethernet can be transmitted over serial or parallel digital circuits.

Front 19

Select the statement that correctly describes one benefit of a router.

Back 19

a.
A router will allow an interface of one data link layer protocol to communicate with an interface using a different data link layer protocol.

Front 20

One of the following scenarios will result in the data encapsulated in a data link layer frame being re-encapsulated into a data link layer frame with a different data-link layer address. Select this scenario.

Back 20

A router receiving an Ethernet frame containing a network layer packet addressed to a node elsewhere on the network.

Front 21

Assume that a network interface card is assigned an IP address of 10.100.65.5 and a subnet mask of 255.255.248.0. From the alternatives below, select the network (subnet) address of this network interface card

Back 21

10.100.64.0

Front 22

Assume that a network interface card is assigned an IP address of 10.100.70.5 and a subnet mask of 255.255.248.0. From the alternatives below, select the network (subnet) address of this network interface card.

Back 22

None of the other answers are correct.

Front 23

Assume that a network interface card is assigned an IP address of 10.100.82.5 and a subnet mask of 255.255.128.0. From the alternatives below, select the network (subnet) address of this network interface card.10.100.82.5 and a subnet mask of 255.255.128.0?

Back 23

10.100.0.0

Front 24

Assuming that Ethernet is used at the data-link layer, select all statements that correctly explain how a network router determines where to route a network packet.

Back 24

The router examines the IP packet at the network layer and determines via the destination field if the packet was destined for itself, or if it should be routed to another subnet.

Front 25

Select all statements that correctly describe the Address Resolution protocol (ARP)

Back 25

A successful ARP request will ultimately lead to the sender receiving a MAC Address of another device on the network.
A successful ARP request will ultimately map an IP Address to an associated MAC Address.

Front 26

Assume that a message exchange between a sender and receiver involves use of continous automatic repeat request (ARQ) as a method of flow control, and that the continous ARQ window size is 4. View the diagram below, and then choose the answer that best explains what will happen after the timeout. Note that the phrase “protocol data unit” is denoted by the acronym “PDU”.

Back 26

None of the other answers are correct.

Front 27

ssume that a message exchange between a sender and receiver involves use of continous automatic repeat request (ARQ) as a method of flow control, and that the continous ARQ window size is 4. View the diagram below, and then choose the answer that best explains what will happen after ACK7 is lost. Note that the phrase “protocol data unit” is denoted by the acronym “PDU”.

Back 27

None of the other answers are correct

Front 28

Select all statements that correctly describe the continuous automatic repeat request (ARQ) method of flow control, assuming that the initial continuous ARQ sliding window size is greater than 1.

Back 28

The receiver can reduce the size of the sliding window to slow down the sender’s send rate.

Front 29

Select all statements that correctly describe why synchronous transmission protocols are more efficient than asynchronous transmission protocols.

Back 29

Synchronous transmission protocols package multiple bytes of data into one frame.

Synchronous transmission protocols perform error and flow control on a per frame basis

Front 30

Given a subnet with a subnet (network) address of 10.100.15.0 and a subnet mask of 255.255.255.0, indicate the number of IP addresses available for client devices on that subnet.

Back 30

254 IP addresses will be assignable to client devices.

Front 31

Given a subnet with a subnet (network) address of 10.100.0.0 and a subnet mask of 255.255.0.0, indicate the number of IP addresses available for client devices on that subnet.

Back 31

none of the other answers are correct

Front 32

Can IP addresses consistently serve to identify hosts (clients)?

Back 32

none of the other answers are correct

Front 33

From the statements below, select all that correctly describe quality of service (QoS) as it concerns data communication networks.

Back 33

QoS can be implemented using a protocol that prioritizes frames at the data link layer.

QoS can be implemented using a protocol that prioritizes packets at the network layer.

Errors in memory can often look different than errors in a physical media (cable).

Front 34

The transport and data-link layers both support error checking. From the alternatives below, select all that correctly explain why error checking can be useful in both layers.

Back 34

Errors in memory can often look different than errors in a physical media (cable).

Front 35

Select all issues that are associated with Wireless LANs (WLANs).

Back 35

With a PCF media access control, a hidden node problem can occur.

WLANs are prone to eavesdroppers.

WLANS are prone to middle man attacks.

Front 36

From the alternatives below, select all that correctly describe Wi-Fi when the 5GHz frequency is used.

Back 36

The 5GHz spectrum is more prone to attenuation than the 2.4GHz spectrum.

The 5GHz spectrum has greater bandwidth then the 2.4GHz spectrum.

The 5GHz spectrum has a shorter range then the 2.4GHz spectrum.

Front 37

From the scenarios below, select all that can cause major performance degradation on a switched Ethernet network.

Back 37

High levels of traffic on the switch and switch buffer overflow.

High levels of traffic on a switch programmed for 802.1q and Quality of Service.

A broadcast storm on the switches.

Front 38

From the alternatives below, select all that correctly describe the Ethernet protocol.

Back 38

Some versions of Ethernet use a shared bus.

Ethernet can operate at relatively high speeds.

Ethernet is relatively inexpensive.

Front 39

From the alternatives below, select all that correctly describe switched Ethernet.

Back 39

Frame collisions cannot occur on a full-duplex, switched network.

Switched Ethernet operates multiple point-to-point links on a network.

Switched Ethernet improves security over Shared Bus Ethernet.

Front 40

Select the method used by the 802.11 Wireless LAN protocols to deal with the “hidden node” problem.

Back 40

Request to Send and Clear to Send packets for channel reservation.

Front 41

From the alternatives below, select all that correctly describe Ethernet.

Back 41

Ethernet is a de facto standard.

All clients are always listening before a transmission begins.

Ethernet uses Cyclical Redundancy Checking to detect errors.

Front 42

From the alternatives below, select all that are cables capable of supporting gigabit transmission.

Back 42

Multi-Mode fiber optic cable

Single-Mode fiber optic cable.

Category 5e UTP

Category 5 UTP

Front 43

From the options below, select all that correctly describe both Distributed Coordination Function (DCF) and Point Coordination Function (PCF).

Back 43

DCF and PCF are CSMA/CA based mechanisms.

DCF and PCF are commonly used with wireless based media.

Front 44

From the options below, select all that correctly describe Distributed Coordination Function (DCF).

Back 44

DCF uses a form of stop-and-wait Automatic Repeat Request (ARQ).

Front 45

From the options below, select all that are design choices which will enhance the strength or performance of a wireless local area network (WLAN) signal.

Back 45

The use of a directional antenna.

Use of a 2.4Ghz WLAN technology instead of a 5Ghz WLAN technology.

Front 46

From the options below, select all that are methods of switching.

Back 46

store and forward

cut through

fragment free

Front 47

A switch that has just been powered on will often broadcast messages to every port until it realizes (via creating a table) the data link layer addresses of devices connected on each port. This will occur even if devices are on differing subnets within this same switch. One of the methods below changes this behavior. When the method is incorporated, the switch will only broadcast packets to a subset of the switches ports. What is this method called?

Back 47

virtual LAN segmentation

Front 48

Select all terms that are protocols which do not support error control.

Back 48

ATM
Frame Relay

Front 49

Select all alternatives that are disadvantages of a routed backbone network.

Back 49

Increased management complexity

Delays due to routing

Front 50

Select all devices that are likely to be connected to the access layer of a network.

Back 50

network printers
client workstations

Front 51

From the alternatives below, select the most common type of backbone network used within the distribution layer.

Back 51

collapsed backbone

Front 52

Select the layer of the internet network model for which a VLAN tag may be specified.

Back 52

data link layer

Front 53

Select the term that is an inter-switch protocol used by multi-switch VLANs.

Back 53

802.1q

Front 54

Select all alternatives that are components in a VLAN tag field.

Back 54

TPID – Tag Protocol Identifier

Priority

CFI – Canonical Format Identifier

VID – VLAN Identifier

Front 55

How many of the available bits in a VID VLAN tag field are used for VLAN identification?

Back 55

12 bit

Front 56

The IEEE Ethernet Frame tagging standard is always required when creating VLANs on a switch.

Back 56

False

Front 57

Consider an organization with stable and predictable MAN/WAN traffic needs of 25Mbps between two sites. Which of the services below are suitable recommendations?

Back 57

Ethernet Services
T3 services
SONET services

Front 58

Consider a multi-site network that is at full capacity. Which options below might be recommended to reduce network demand?

Back 58

using data compression technology.

shifting network usage from peak to low demand times.

configuring devices such as network printers to use a single broadcast protocol rather than many (IPX, TCP/IP, LAT, SNA, NetBEUI etc.)

moving data closer to users.

Front 59

When compared to the other WAN architectures, a full mesh WAN architecture provides the most benefits. Why is it not routinely deployed?

Back 59

The cost to connect every campus to every other campus is usually too high.

Front 60

Select all statements that correctly describe T1.

Back 60

A T1 frame is composed of 24 channels. Each channel takes turn outputting 8 bits to the frame.

A T1 is 1.544Mbps. However, only 1.536Mbps is usable.

A T1 can be multiplexed or de-multiplexed (IMUX) to provide more or less capacity.

Front 61

Select all statements that correctly describe the core layer of backbone networks.

Back 61

The core layer is the layer in the BN that connects different BN’s together.

The core layer is connected to the distribution layer on the backbone network.

The core layer can feature routers or switches depending on the network architecture.

Front 62

Select all alternatives that are disadvantages of collapsed backbones.

Back 62

They require longer cable runs.

They have an increased broadcast domain.

They have a single point of failure.

Front 63

Select all statements that correctly describe a benefit of a VLAN.

Back 63

A VLAN can be a benefit when trying to secure a network.

A VLAN can be given a tag to associate it with a particular VLAN ID.

VLANs can make use of Quality of Service (QoS) for traffic prioritization.

Front 64

Two of the following are true regarding VLAN tags. Select exactly two.

Back 64

A VLAN tag is stripped from the packet once it gets processed by a router.

A VLAN tag can be passed through a trunk port from one switch to another.

Front 65

Select all alternatives that are a valid type of VLAN.

Back 65

MAC Address (Data Link layer) based VLANs

Switch Port based VLANs
IP layer based VLANs

Application layer based VLANs

Front 66

From the statements below, select all that correctly describe a property of the source data units in datagram switching.

Back 66

Source data units may take a separate path to the destination node.

Source data units move simultaneously to the destination node.

Front 67

Select all statements that correctly describe contention based media-access control.

Back 67

Contention based media-access control is not used by the Token Ring protocol.

Contention based media-access control offers its best performance when the volume of traffic is low.

Contention based media-access control is used by the Ethernet protocol.

Front 68

Match each technology to its most used media access control technique.

Back 68

Point Coordination Function (PCF)

Frequency-hopping spread spectrum (FHSS)

Carrier Sense Multiple Access - Collision Detection (CSMA/CD)

Distributed Coordination Function (DCF)

Front 69

From the options below, select all that correctly describe a way 802.16d WiMax and 802.16e WiMax differs.

Back 69

802.16d is used in fixed point wireless solutions, while 802.16e is in mobile use wireless solutions.

802.16e is a competitor for public WiFi hotspots, while 802.16d is more commonly used to chain wireless access points across farther distances.

Front 70

An IPSec virtual private network (VPN) will utilize methods to secure a message before sending it to its destination. This is accomplished by wrapping the Network, Transport, and Application layer PDUs with a packet of another protocol. What is this protocol called?

Back 70

Encapsulating Security Payload

Front 71

Select all statements that correctly describe an IPSec virtual private network (VPN).

Back 71

An IPSec VPN uses the UDP protocol at the transport layer.

An IPSec VPN encrypts at the network layer.

Front 72

Select all alternatives that are types of symmetric encryption.

Back 72

AES

3DES

Front 73

Select all statements that correctly describe asymmetric encryption.

Back 73

Asymmetric encryption generally uses complex algorithms.

Asymmetric encryption is often used in conjunction with symmetric encryption.

Front 74

Select all statements that correctly describe a firewall.

Back 74

A firewall can be application, packet, and NAT based.

An application firewall can block traffic based on incoming traffic’s application layer port.

A firewall can implement access control lists to secure network traffic between interfaces.

Front 75

Select all statements that correctly describe Kerberos.

Back 75

Kerberos authentication does not send passwords across the network.

Kerberos generates a session key for clients, and clients use this session key to authenticate themselves.

Kerberos is often used in Directory Services.

Front 76

Select all statements that correctly describe the Secure Sockets Layer (SSL) protocol.

Back 76

SSL operates between the application layer and the transport layer.

After an SSL session has been initiated, a suitable encryption method is chosen by both the sender and receiver.

Front 77

Select the kind of network that most closely describes how Internet Service Providers (ISPs) are organized.

Back 77

A hierarchical network

Front 78

Select all alternatives that are organizations that play a role in internet governance.

Back 78

IANA

IETF

ICANN

Front 79

Select all protocols that were developed by the Internet Engineering Task Force (IETF) organization.

Back 79

DHCP

Front 80

Select the correct definition of non-repudiation.

Back 80

None of the other answers is correct.

Front 81

Select all alternatives that are principle requirements that network security addresses.

Back 81

Confidentiality

Integrity

Front 82

From the kinds of network security attacks below, select all that are active attacks in which the attacker sends some kind of transmission.

Back 82

Node A masquerading as Node B by claiming Node B’s MAC address

A hacker sending ICMP packets to a web server at a rate that cripples the server

A hacker intercepting a message, modifying its contents, and transmitting this modified message to the original receiver

Front 83

Select all alternatives that correctly describe hashing which occurs at the media-access control (MAC) layer, for example MD5 and SHA-1.

Back 83

MAC hashing is a tool used by the data-link layer to help determine if a message has been altered.

Front 84

Select all that would be significant challenges if an organization chose to secure their network solely with symmetric encryption.

Back 84

Symmetric encryption does not provide built-in key management mechanisms; therefore, key management could be a significant challenge.

Front 85

Select all alternatives that are a security service that digital signatures provide.

Back 85

Integrity

Authentication

Non-Repudiation

Front 86

Select the entity that is responsible for maintaining a Certificate Revocation List (CRL).

Back 86

The certifying authority that issued the certificate.

Front 87

Select all alternatives that correctly describe Key-Hashed Message Authentication Codes (HMACs).

Back 87

HMACs provide authentication.

HMACs do not require a key management infrastructure.

Front 88

Select the organization responsible for allocating blocks of IP addresses.

Back 88

IANA

Front 89

Select the organization responsible for administering the allocation of domain names.

Back 89

ICANN

Front 90

Select all options below that can be a disadvantage of selecting network equipment from multiple vendors.

Back 90

vendors might not follow standards precisely and therefore two different vendor products might be have interoperability issues.

vendor products might be incompatible due to different interpretations of the same standard.

Front 91

Select the version of SNMP that provides for authentication.

Back 91

SNMP v3

Front 92

SNMP was originally designed to use a connectionless transport protocol. Select the earliest version of SNMP that was designed to use a connection-oriented transport protocol instead.

Back 92

SNMP v3

Front 93

Select all levels of network management that are typically the responsibility of the managed devices on the network.

Back 93

Sensor level

Agent level

Front 94

Each managed network device stores data it gathers in its own virtual database. Select the name of this kind of virtual database.

Back 94

Management Information Base

Front 95

Select all methods that can improve an existing network's uptime.

Back 95

Using redundant network devices in critical locations.

Using battery backup devices such as a UPS or generator to power equipment.

Using network load balancers across a cluster of servers.

Using robust virus and malware protection on client and server machines.

Front 96

Select the alternative that is the correct definition a network partition.

Back 96

A subnet on the network that is made inaccessible to other subnets due to connection failure.

Front 97

Select all correct descriptions of performance management on a network.

Back 97

Performance management involves investigating the changes in network traffic patterns and adjusting network policies that might affect these patterns.

Front 98

Select all correct descriptions of fault management on a network.

Back 98

There are two parts to fault management – Operational Response and Fault Management.

Front 99

Select the standardized network management protocol that was created first.

Back 99

IEEE 802.1

Front 100

Select all management protocols that were initially proposed by the Internet Engineering Task Force.

Back 100

SNMP
HEMS

Front 101

Select all correct explanations as to why traditional network design is not suitable for modern networks.

Back 101

Technology changes rapidly in modern networks.

Modern networks experience unprecedented traffic growth.
The complexity of devices has increased, requiring additional management time, which increases staffing costs.

Front 102

Select all alternatives that are key phases in the building block network design process.

Back 102

Technology Design phase

Cost Assessment phase

Needs Analysis phase

Front 103

Select all alternatives that are significant differentiators between the building block network design process and the traditional network design process.

Back 103

The building block approach uses an iterative process to refine the network design.

Front 104

Select all alternatives that are goals of "baselining."

Back 104

To provide a clear picture of the current sequencing of operations.

To provide a baseline for current processing times for operations.

Front 105

Select all alternatives that are deliverables in the Needs Analysis phase of the building block network design process.

Back 105

A list of mandatory applications the network should support.

Front 106

Select all alternatives that are elements included in the Technology Design phase of the building block network design process.

Back 106

The specification of base and advanced level computers to associated typical and high traffic areas.

Deciding on specific technology for circuits (i.e. T3, Ethernet, etc.)

An estimation of average circuit traffic.

An estimation of peak circuit traffic.

A mathematical simulation (model) of the behavior of the network.

Front 107

Select all correct descriptions of load balancing and server clustering in a network.

Back 107

The effects of a server failure can be mitigated when another server activates to take the processing load.

Servers receive load balanced requests via various mechanisms, including the “round robin” method.

Front 108

Select all reasons why content caching and delivery approaches reduce network traffic.

Back 108

Content delivery devices can store resources on many servers located in key geographical locations, many of which are close to the clients requesting the resources.

Front 109

Select all devices that can be managed with SNMP.

Back 109

Routers
Switches

Printers

UPSs

Gateways

Front 110

Select all alternatives that are problems associated with Management Information Bases (MIBs).

Back 110

Standards committees have not imposed commonality with MIBs.

There is a proliferation of MIBs on the market, adding to the complexity of their use.

Front 111

Select all characteristics exhibited on properly managed, large network.

Back 111

scalability

commonality

orthogonality

Front 112

A(n) _____________ is a set of rules that determine what a layer would do and provides a clearly defined set of messages that software at the layer needs to understand.

Back 112

protocol

Front 113

Which layer of the OSI model is responsible for ensuring that all packets sent are received by the destination station by dealing with end-to-end issues?

Back 113

transport Layer

Front 114

The most commonly used e-mail standard is:

Back 114

Simple Mail Transfer Protocol

Front 115

The American National Standards Institute:

Back 115

is the coordinating organization for the United States' national system of standards

Front 116

Which standards body is responsible for the development of local area network (LAN) standards?

Back 116

IEEE

Front 117

In the Internet model, the application layer corresponds to the ________, layer(s) s of the OSI model.

Back 117

session, presentation and application

Front 118

With a client-based architectures, one fundamental problem is that:

Back 118

all data on the server must travel to the client for processing

Front 119

A(n) __________ is the way in which the functions of the application layer software are spread among the clients and servers in the network.

Back 119

application architecture

Front 120

A "thin client" architecture approach:

Back 120

places all or almost all of the application logic on the server

Front 121

The protocol that makes it possible for a Macintosh web browser to be able to retrieve a Web page from a Microsoft Web server is called _____________________.

Back 121

Hypertext Transfer Protocol

Front 122

Which of the following statements is correct?

Back 122

Serial transmission is slower than parallel transmission.

Front 123

Select all terms that correctly identify hardware or software that is used to transform analog voice signals to digital signals and digital signals to analog signals.

Back 123

codec

Front 124

The _____________ of a circuit determines a circuit's capacity.

Back 124

When sending four bits at a time using frequency modulation, the number of different frequency levels that would be needed would be _______.

Front 125

A coding scheme that uses 12 bits to represent each character is capable of representing _________ different characters.

Back 125

4096

Front 126

How many bits per sample are required to sample an incoming signal 4,000 times per second using 64 different amplitude levels?

Back 126

6

Front 127

Which of the following media has the lowest error rates and the highest transmission speeds?

Back 127

fiber optic cable

Front 128

Select all alternatives that correctly describe point-to-point circuits.

Back 128

Point-to-point circuits are called dedicated circuits.

Point-to-point circuits are dedicated to the use of the two computers

Front 129

Which of the following media can best withstand harsh environmental conditions?

Back 129

fiber optic cable

Front 130

If each sample uses 16 bits, and the number of samples taken each second is 2,000, then what is the transmission speed of the circuit?

Back 130

None of the other answers are correct

Front 131

Synchronous transmission:

Back 131

is used to transmit a "frame" or "packet" of data at a time

Front 132

When a network protocol utilizes Automatic Repeat Request (ARQ), a NAK:

Back 132

is sent by the recipient if the message contains an error

Front 133

The loss of power a signal suffers as it travels from the transmitting computer to a receiving computer is:

Back 133

attenuation

Front 134

________ is the process of sending a signal to a client that gives its permission to transmit or asks it to receive.

Back 134

Polling

Front 135

_______________ is an effective way to deal with attenuation.

Back 135

Adding repeaters or amplifiers to a circuit

Front 136

Which items in the list below can cause errors during data transmission?

Back 136

White noise, Impulse noise, Echo, Cross talk

Front 137

When a network protocol utilizes Automatic Repeat Request (ARQ):

Back 137

a receiver that detects an error in a message simply asks the sender to retransmit the message

Front 138

Which of the following is true about the data link protocol PPP?

Back 138

it is a byte-oriented protocol

Front 139

Select all of the alternatives that are capabilities of the data link layer.

Back 139

flow control
error detection and correction
medium access control

Front 140

Select all of the alternatives below that are controlled access methods.

Back 140

Poll/select

Token passing

Front 141

IPv4 Network Layer addresses are how many bits long?

Back 141

32

Front 142

Select all of the alternatives below that describe an action taken to address IP address exhaustion.

Back 142

The introduction of a private addressing scheme
When block of addresses were distributed, fewer were given out and some large class A blocks were re-claimed
Development of a new version of IP

Front 143

Routing between autonomous systems is called _______ routing.

Back 143

exterior

Front 144

How many unique identifiers would a 17-bit address field provide? Include any broadcast and network addresses identifiers in your calculation.

Back 144

131,072

Front 145

Assume that a network interface card is configured as follows:
IP Address: 192.168.43.3
Subnet Mask: 255.255.255.248
Select the subnet-directed broadcast address from the alternatives below.

Back 145

192.168.43.7

Front 146

Select all statements that correctly identify differences between TCP and UDP.

Back 146

TCP segments have bits to track sequences of packets, UDP datagrams to not track packet sequences.

UDP is connectionless while TCP is connection based.

Front 147

How many TCP fragments can be put in an IP packet?

Back 147

1

Front 148

TCP has a nominal 20 byte header for all PDUs. Some protocols have a separate type of PDU that carry no data for sending acknowledgments and flow control. Imagine that a new version of TCP utilized these seperate acknowledgment and flow control PDUs. How many bytes could be removed from the existing TCP header for the standard TCP PDU?

Back 148

6

Front 149

In a reliable transport service such as TCP, if a packet is duplicated, _______.

Back 149

one of the duplicates is discarded

Front 150

Assume there is a log which contains the following TCP/IP related information for TCP/IP network traffic on a local area network: Source IP address Destination IP address Source port Destination port What information would be needed to uniquely identify a TCP connection?

Back 150

Source IP address, Destination IP address, Source port, Destination port

Front 151

When the destination device receives a Ethernet frame with a bad CRC, the device does which of the following?

Back 151

Discards the frame

Front 152

Review the diagram below, then follow the subsequent instructions:

Back 152

Select the protocol that that switches in this diagram must support, if a frame from the external network is to successfully reach a node on the LAN.

802.1D Spanning Tree protocol.

Front 153

From the alternatives below, select all that correctly describe a MAC address.

Back 153

A MAC address is a data-link layer address.

Front 154

Switched Ethernet:

Back 154

usually enables all attached circuits to send or receive packets simultaneously

Front 155

802.11g is backward compatible with which type of WLAN?

Back 155

802.11b

Front 156

Which of 802.11 standards offer additional security for WLAN applications?

Back 156

802.11i

Front 157

What is the maximum cable segment length for 10Base-T when using 100 Ohm unshielded Twisted Pair cable?

Back 157

100 meters

Front 158

Which security system changes the key for every frame it transmits to the client.

Back 158

WPA

Front 159

Select the form of media access control that Ethernet uses.

Back 159

Carrier Sense Multiple Access/Collision Detection

Front 160

Ethernet is a ___________ protocol, which means that there is no guarantee on the delivery time of a message.

Back 160

Non-deterministic

Front 161

Which of the following is not true about CSMA/CD?

Back 161

It is used in token ring protocol LANs

Front 162

Select all statements that correctly describe the data link layer.

Back 162

The data link layer manages the physical layer.

The data link layer is comprised of two sub layers that each have their own responsibilities.

Front 163

Select all statements that correctly describe the network layer.

Back 163

The network layer interfaces with both the transport layer and the data link layer.

The most-used network layer protocol is IP.

Routers operate at the network layer.

Front 164

Most Countries, permit WLANs to operate in two frequency ranges that have been reserved for unlicensed transmissions those are

Back 164

the 2.4GHz range and the 5GHz range

Front 165

From the alternatives below, select all that correctly describe Wireless LANs (WLANs).

Back 165

WLANS are effectively Half Duplex.

WLANs effectively use a shared bus architecture.

Front 166

A ________ is a software that contains components and programs that allow a computer on a network to serve requests from other computer for data and provide access to other resources such as printer and file systems.

Back 166

Network operating system

Front 167

If your LAN server is overloaded, which of the following should you not consider to solve the server problem?

Back 167

replacing the cable with fiber optic cable

Front 168

A Bluetooth network is called a(n) _________, which consists of no more than ______ slave devices, in addition to a master device.

Back 168

Piconet, 7

Front 169

When an access point configured to use EAP first discovers a new client the first thing the access point does is:

Back 169

requires the user authenticate against a login server

Front 170

Select the alternative which correctly indicates the duration, in microseconds, of a transmission of 4 bits on a 10 Gbps network.

Back 170

.0004 microseconds

Front 171

Select all statements that correctly describe backbone architecture layers.

Back 171

The core layer is the part of the backbone which connects the different backbones together.

The distribution layer is the part of the backbone that connects the LANs together.

Front 172

Improving circuit capacity on a backbone network is one way to increase the network's performance.

Back 172

True

Front 173

Select all statements that correctly describe layers, switches, and gateways.

Back 173

Routers connect two or more network segments that use the same or different data link protocols.


Layer-2 switches may connect the same or different types of cable.


Multi protocol routers can route but not translate between several different network layer protocols.


Gateways connect two or more networks that use the same or different data link and network protocols.

Front 174

Select all alternatives that correctly describe broadcast messages.

Back 174

The majority of broadcast messages usually occur at the data link layer.


Broadcast messages can place a lot of demand on backbone networks.


Broadcast messages usually consume more network resources on switched backbones than on routed backbones.

Front 175

Select all statements that correctly describe computers and devices that are part of a backbone network.

Back 175

Some devices in a routed backbone network would include routers that might route packets to different subnets.


Most backbone devices are store-and-forward devices.

Front 176

Assume that there is a wide-area network (WAN) where the capacity of all its circuits and devices is currently being utilized. Select all statements that correctly describe ways to improve the performance of this WAN.

Back 176

Upgrading the maximum bit-rate of circuits in the WAN
Upgrading the memory, processor, or I/O subsystem on the devices which connect the backbone networks to the WAN
Replacing the devices which connect the backbone networks to the WAN with more powerful devices

Front 177

Select all statements that are correct in the context of a a wide-area network (WAN).

Back 177

Circuits on a WAN that are not used to capacity can usually be downgraded to save on cost.

Adding a packet-switched service that is used only when demand exceeds circuit capacity is one way to improve performance on a WAN.

Front 178

What technology, under ideal conditions, will provide data rates up to 70 Mbps for up to 30 miles?

Back 178

WiMax

Front 179

A Basic rate interface provides communication circuit with _____ digital transmission channel and ____ control signaling channel.

Back 179

Two 64 Kbps, one 16-Kbps

Front 180

Assume that a dedicated-circuit network is using a ring architecture, and that the network is operating close to its capacity. If there is a failure of any one circuit, the transmission times will dramatically ___________.

Back 180

increase

Front 181

Choose all that are features of ATM networks. ATM networks _________________.

Back 181

perform encapsulation of packets
are scalable
provides extensive QoS information

Front 182

Select all alternatives that would likely increase demand on a regional wide-area network.

Back 182

Moving data further from the applications and people who use them.

Front 183

Select all statements that correctly describe the routed backbone architecture.

Back 183

Routers are usually more expensive than switches.


Routed backbones do not forward data-link layer broadcast messages.


Routing takes more time than switching.

Front 184

Select all statements that correctly describe gateways as a backbone network component.

Back 184

The highest layer some gateways operate at is the application layer.


The highest layer some gateways operate at is the network layer.


One common use of gateways is the enable LANs that use TCP/IP and Ethernet to communicate with mainframes that use other protocols

Front 185

The highest layer most switches operate at is the __________ layer.

Back 185

data link

Front 186

Switched backbone architectures use a(n) _____________ topology.

Back 186

star

Front 187

The VLAN environment is transparent to the sending and receiving computer.

Back 187

True

Front 188

A _______________ is particular type of network that uses circuits that run over the Internet but that appears to the user to be a private network.

Back 188

virtual private network

Front 189

In the context of a virtual private network, a tunnel can most accurately be described as _________________________.

Back 189

a virtual circuit through the Internet.

Front 190

Select all terms that are VPN tunneling protocols.

Back 190

IPSEC
L2TP

Front 191

Which one of the following aspects of public/private key encryption provides authentication?

Back 191

The fact that a digital signature encrypted with a user's private key can be decrypted with that user's public key and matched to the network message.

Front 192

___________ refers to the fact that ISPs do not charge one another (at the same level) for transferring messages they exchange across an NAP or MAE.

Back 192

Peering

Front 193

A(n) ___________ contains a series of cable modems/multiplexers and converts the data from cable modem protocols into protocols needed for Internet traffic, before passing them to a router connected to an ISP POP.

Back 193

cable modem termination system

Front 194

DSL modems, cable modems, and dial-up modems connect to a ___________ , which is used by ISPs to authenticate its customers.

Back 194

remote-access server.

Front 195

The most important elements of the disaster recovery plan are _________ and ________ that enable the organization to recover its data and restart its application software should some portion of network fail.

Back 195

backup and recovery controls

Front 196

Asymmetric DSL uses ___________ multiplexing to create three separate channels over one local loop circuit.

Back 196

frequency division

Front 197

Select all alternatives below that are methods by which a secret key can be securely exchanged between two entities Entity A and Entity B.

Back 197

TTP (trusted third party) delivering key to both Entity A and Entity B.

d.
Entity A physically delivering the key to Entity B.

Front 198

A __________ is a trusted organization that can vouch for the authenticity of the person or the organization using the authentication.

Back 198

certificate authority

Front 199

What is the difference between VPNs and firewalls?

Back 199

Providing a long-distance connection between two regional wide-area networks.

c.
Providing Internet access to remote office buildings, apartment buildings, and hotels.

Front 200

________________ is in use when the set of hundreds of copper telephone lines that run from the telephone switch office is replaced by one fiber-optic cable that is run past each house or office in the neighborhood.

Back 200

Passive Optical Networking

Front 201

Select all statements that correctly describe accessing the Internet.

Back 201

Users can connect to the Internet by using passive optical networking technologies.


Users can connect to the Internet by using DSL.


Users can connect to the Internet by using a 56 Kbps dial up modem.


Users can connect to the Internet by using WiMax technologies.


Users can connect to the Internet by using satellite technologies.

Front 202

The ________ is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and smooth operation of the Internet, which has working groups and produces Requests For Coments and other relevant technical documents that influence the way people design, use, and manage the Internet

Back 202

Internet Engineering Task Force

Front 203

Select all alternatives that are groups that developed Internet 2.

Back 203

UCAID

Front 204

Select all alternatives that are fundamental techniques to determine if an intrusion is in progress in a stable network.

Back 204

anomaly detection

Front 205

Select all statements that correctly describe network controls.

Back 205

Regardless of the effectiveness and number of controls on a network, an individual or department should still be responsible for the network's security.


Network controls can prevent, detect, and correct security breaches on a network.


Developing network controls for a network is vital to that network's security.


Controls should be examined on a regular basis to help ensure their effectiveness.

Front 206

Procedures, rules, hardware, and software that correct, prevent, or detect breaches in security are best classified as:

Back 206

network controls

Front 207

A (n) ______ is a special type of malware, not attached to any other program that spreads itself from computer to computer, without human intervention.

Back 207

worm

Front 208

A control spreadsheet used in risk assessment lists the __________, ________ and ________ that a network manager uses to assess the level of risk.

Back 208

Assets, threats, and controls

Front 209

Attacks that take advantage of a newly discovered security hole before a patch is developed are called ________ .

Back 209

Zero day attacks

Front 210

modulation

Back 210

when we transmit data through telephone lines, we use the shape of the sound waves we transmit (in terms of amplitude, frequency, and phase) to represent different data values. We do this by transmitting a simple sound wave through the circuit (called a carrier wve) and then change its shape in different ways to represent a 1 or a 0. Modulation is the technical term for shape changes. Three fundamental types: amplitude, frequency, and phase modulation.

Front 211

amplitude modulation

Back 211

also called amplitude shift keying, the amplitude, or the height, of the wave is changed. One amplitude is the symbol defined to be 0, another is the symbol defined to be one. When one wishes to send a 1, it sends a high amplitude signal, when 0, a low.

Front 212

frequency modulation

Back 212

also called frequency shift keying, is a modulation technique whereby each 0 or 1 is represented by a number of waves per second. one frequency is defined to be a symbol of 1, and a different frequency is the symbol defined to be a 0.

Front 213

phase modulation

Back 213

also called phase shift keying. phase refers to the direction in which the wave begins. waves can also start down and to the right (known as a phase of 180*) with phase modulation, one phase symbol is defined to be a 0 and the other phase symbol is defined to be a 1. 0* can be a zero, 180* can be a 1.

Front 214

quadrature amplitude modulation (QAM)

Back 214

involves splitting the symbol into eight different phases(3 bits) and two different amplitudes (1 bit) for a total of 16 possible values.Thus, one symbol in QAM can represent 4 bits, while 256-QAM sends 8 bits per symbol. 64-QAM and 256-QAM are commonly used in digital TV services and cable modem Internet services.

Front 215

bit rate

Back 215

the number of bits per second

Front 216

baud rate

Back 216

the number of times a second that the communication circuit changes

Front 217

Five layer networking model

Back 217

serves primarily the protocols known as TCP and IP, jointly TCP/IP. The User datagram protocol is also served by this model. The internet model evolved from the work of thousands people who developed pieces of the Internet

Front 218

physical layer

Back 218

the physical layer is the physical connection between the sender and receiver. Its role is to transfer a series of electrical, radio, or light signals through the circuit. The physical layer includes all the hardware devices and physical media.

Front 219

The data link layer

Back 219

is responsible for moving a message form one computer to the next computer in the network path from the sender to the receiver. The data link layer in the Internet model performs the same three functions as the data link layer in the OSI model. First it controls the physical layer by deciding when to transmit messages over the media. Second, it formats the messages by indicating where they start and end. Third, it detects and may correct any errors that have occurred during transmission.

Front 220

the network layer

Back 220

it performs routing, in that it selects the next computer to which message should be sent. second, it can find the address of that computer if it doesnt already know it.

Front 221

application layer

Back 221

the application software used by the network users and includes much of what the OSI model contains in the application, presentation, and session layers. The users access to the network.

Front 222

datalink layer

Back 222

ethernet frame- the data link layer formats the message with start and stop markers, adds error checking information, places the IP packet inside an ethernet PDU, whihc is called an Ethernet frame, and instructs the physical hardware to transmit the Ethernet frame, which contains the IP packet.

Front 223

network layer

Back 223

IP- The network layer on the Internet uses a protocol called IP which has its rules and PDUs. IP selects the next stop on teh message's route through.It places the TCP segment inside an IP PDU.

Front 224

application layer

Back 224

HTTP

Front 225

Processes and application layer

Back 225

Provides applications services to users and programs

Front 226

transport layer

Back 226

handles data consistency functions, provides a reliable byte stream between two

Front 227

Internet(network) layer

Back 227

provides network addressing and routing, and does so in such a way as also to provide common address space across multiple lower level protocols. this makes possible the interconnection of networks that characterizes the Internet. The IP protocol operates at this level

Front 228

network (datalink) layer

Back 228

This layer contains whatever IP will run over, ethernet, token-ring, and FDDI.

Front 229

physical layer

Back 229

referrers to all hardware under the network layer

Front 230

encapsulation in terms of networking

Back 230

this happens when a PDU at a higher level is put inside the PDU of a lower level. The opposite is known as decapsulation

Front 231

standards a standard defines a set of rules

Back 231

called protocols

Front 232

application architectures

Back 232

the way in which the functions o fhte application layer software are spread among the clients and servers in the network. divided into four general functions (data storage, data access logic, application(business) logic, and presentation logic

Front 233

data storage

Back 233

where the data is stored and retrieved

Front 234

data access logic

Back 234

the processing required to access the data

Front 235

presentation logic

Back 235

the presentation of information to the user and the acceptance of user commands

Front 236

host-based architectures

Back 236

the server performs all the work, usually a large mainframe computer, while the clients were typically terminals. The clients meerly captured keystrokes, sent them to the server for processing, and accepted instructions from the server on what to display. Two problems, first the server must process all the messages and these types of architectures are usually expensive to upgrade

Front 237

client-based architectures

Back 237

the client performs all the work. with client-based architectures, the clients are personal computers on a lan and the server is usually another personal computer on the same network. When a client-based architecture is in place, the clients are personal computers on a lan, and the server is usually another personal computer on the same network. The server essentially acts as a storage device. Storing a document on the file server after being written in a word processor is an example of this architecture in place. Fundamental problem is that all data on the server must travel to the client for processing. This can overload network circuits.

Front 238

client-server architectures

Back 238

the work is shared between the servers and clients. There is some division of the responsibility among the client and the server. Using a web browser to get pages from a web server is using a client-server architecture. A strength of this architecture is that they enable software and hardware from different vendors to be used together. Middleware is typically used to ease this process

Front 239

peer-to-peer architectures

Back 239

the computers are both clients and servers. These can be installed anywhere on the network, even globally, very resilient to the failure of any one computer. Difficulty is finding the data.

Front 240

Two-tier

Back 240

the server is responsible for the data and the client is repsonsible for application and data. Two sets of computers, one set of clients.

Front 241

Three-tier

Back 241

three sets of computers

Front 242

thin-client

Back 242

places little or no application logic on the client

Front 243

thick-client

Back 243

places all or almost all of the application logic on the client

Front 244

scalability

Back 244

the client-server architecture provides the best scalability, or the ability to increase (or decrease) the capacity of the servers to meet changing needs.

Front 245

Http request

Back 245

has three parts- the request line, the request header, and the request body

Front 246

http response

Back 246

has an http response status, a response header, and a response body

Front 247

multiplexing

Back 247

breaking on high-speed physical communication circuit into several lower-speed logical circuits so that many different devices can simultaneously use it. Done in multiples of four. Four type of multiplexing: Frequency Division Multiplexing (FDM), time division multiplexing (TDM), statistical time division multiplexing (STDM), and wave-length division multiplexing (WDM).

Front 248

Frequency division multiplexing

Back 248

dividing the circuit horizontally so that many signals can travel a single communication circuit simultaneously. Each channel is a separate logical circuit, and the devices connected to them are unaware that their circuit is being multiplexed. Guardbands are the unused portions of the circuit that separate these frequencies from each other. Total capacity is divided by the number of circuits + guardbands

Front 249

Time Division Multiplexing

Back 249

Shares a communication circuit among two or more computers by having them take turns, dividing the circuit. There are no guardbands, so it's more efficient.

Front 250

Statistical Time Division Multiplexing

Back 250

statistical analysis to mutliplex

Front 251

Inverse Multiplexing

Back 251

combines several low speed circuits into one high speed circuit BONDING

Front 252

Data rate

Back 252

signifies the rate of bits over a connection, meaning the number of bits that flow per a period of time (usually seconds

Front 253

transmission efficiency

Back 253

indicates the percentage of the informational data sent with respect to the total data sent. the total data sent includes the overhead data needed by the network protocols

Front 254

transmission efficiency

Back 254

the number of information bits/total number of bits transmitted. transmission efficiency(2)

Front 255

transmission efficiency(3)

Back 255

the overhead header and footer bits must be summoned from all protocols invloved for a transmission, to determine the number of overhead bits.

Front 256

effective data rate

Back 256

transmission efficiency * maximum data rate

Front 257

ip addressing

Back 257

has an address written in the form 192.168.1.1 for one node to reach another node using the ip protocol, it must know its IP address. each node can send packets directly on the same subnet.

Front 258

subnet

Back 258

a subnet provides a way to divide LANs by logically grouping nodes by IP number

Front 259

subnet mask

Back 259

uses a subnet mask to determine if the address is on the same subnet

Front 260

subnet formula

Back 260

Bitwise and source IP with subnet mask Bitwise and destination IP with subnet mask If both results are equal, the node is in the same subnet. Send it directly. If both results are not equal, the node is in a different subnet. Use the routing table to determine where to send it, usually to the default gateway.

Front 261

wide area network(WAN)

Back 261

connect backbone networks and regional WANs across any distance, when organizations use WANs they have a need for a private network to span campuses located geographically far apart

Front 262

sl

Back 262

dsl is a family of techniques that combines analog transmission and FDM to provide a set of voice and data circuits. There are many different types of DSL. A DSL modem, called customer premises equipment (CPE), is installed in the customer's home. The modem is first and FDM device that splits the physical circuit into three logical circuits: standard voice, upstream and downstream. TDM is then used within the two data channels to provide a set of one or more individual channels that can be used to carry data.

Front 263

Broadband technologies

Back 263

higher speed communications than traditional modems. Internet technologies cannot be used for general purpose networking

Front 264

DSL

Back 264

a family of point-to-point technologies designed to provide high-speed data transmission over traditional telephone lines. The CPE in DSL includes a line splitter that is used to separate the traditional voice telephone signals into the normal telephone system. If data fails, normal phones are not affected. Local loops are connected to the Main Distribution facilitiy, which works like the CPE line splitter. DSL Access Multiplexer converts it into ATM data. DSL is a point to point technology

Front 265

ADSL

Back 265

uses frequency division multiplexing to create three separate channels over the local loop circuit. ADSL is asymmetric because the upload and download speeds are not the same.

Front 266

Cable

Back 266

Data over cable service interface specification DOCSIS. Hybrid fiber coax networks. Cable modems use shared multipoint circuits, each user is competing with other users for the available capacity. The cable runs to an optical fiber node, which has an optical-electrical converter to convert between the coaxial cable and the fiber wire. The fiber nodes are connected to the cable company distribution hub through two seaparate circuits (upstream/downstream)

Front 267

Cable modem termination system (CMTS)

Back 267

a series of cable modems/multiplexers and converts the data from cable modem protocols into protocols needed for internet traffic. Downstream contains ordinary video and data.

Front 268

fixed wireless

Back 268

the commercial name for a set of standards developed by the IEEE. Can be used to connect a house or an office into the Internet. Works much in the same way as wifi. WiMax uses the 2.3 2.5 and 3.5 frequency ranges. Maximum ranges from 3 to 10 miles, depending interference and obstacles

Front 269

wireless broadband

Back 269

wimax

Front 270

symmetric encryption

Back 270

single-key encryption has two parts, the algorithm and the key. In symmetric encryption, the communicating parties must share the one key. Because the same key is used to encrypt and decrypt, key management can be important

Front 271

data encryption standard (DES)

Back 271

older version of the new 3DES standard

Front 272

Advanced encryption standard

Back 272

128,192,256 bits

Front 273

asymmetric encryption

Back 273

Public key encryption, RSA, Public Key Infrastructure PKI, public key encryption is inherently different from symmetric single-key systems like DES. There are two keys one, the public key, is used to encrypt the message, and a second, a private key, is used to decrypt. 512, 1024, 2048

Front 274

3. (10 pts) Assume that you are running HTTP 1.0, and requesting an HTML page which contains two images in addition to the HTML content. How many request response pairs would there be in such a scenario? Describe how a Web browser and a Web server work together to send a Web page to a user in the above scenario.

Back 274

.

Front 275

7. (10 pts) How does digital data differ from analog data?

Back 275

.

Front 276

(20 pts) Assume we need to download the text of a paperback book at the rate of 30 pages per minute. Further assume that the number of lines per page is 23, and the number of characters per line is 65. What is the required bit rate of the channel? Show all of your work for full credit.

Back 276

.

Front 277

10 pts) Assume that a node SENDER wants to transmit a message to a node RECEIVER at the data link layer. Review the scenarios below, which describe the success or failure of the initial transmission of the message or the ACK. For each scenario, indicate a complete and numbered series of steps describing exactly how the SENDER and RECEIVER successfully transmit the message. The last step for each scenario should be the successful acknowledgment from the receiver.

If you are having difficulty with this problem, it may help you to draw the numbered steps (drawing the steps is optional).

Scenario 1: The message is initially transmitted with an error.
Scenario 2: The message is transmitted without an error.
Scenario 3: The ACK for the message is initially lost.
Scenario 4: The message is initially lost.

Back 277

.

Front 278

Identify and explain three important factors to consider when determining whether to use a large or a small frame (or PDU – protocol data unit) size when transmitting data over a network.

Back 278

.

Front 279

3. (10 pts) Determine the effective data rate of a 128 kbps connection in an asynchronous transmission using 7-bit ASCII, 1 parity bit, 1 start bit, and 1 stop bit. Show your work to receive credit.

Back 279

.

Front 280

A web browser sends a message using HTTP over TCP/IP over Ethernet. The web browser request consists of 130 bytes. The HTTP protocol adds an additional 50 bytes of overhead to the request as part of the HTTP PDU. There is neither noise nor errors on the circuit involved in the transmission.

Calculate the overall transmission efficiency of the web browser's request. You may assume that nominal TCP and IP headers are used, both of which consist of 20 bytes. Show your work to receive credit.

Back 280

.

Front 281

PGP

Back 281

a freeware public key encryption package developed by phillip zimmermann

Front 282

Secure Sockets Layer

Back 282

Is an encryption protocol widely used on the web. Operates between the application layer software and the transport. It encrypts outbound packets comoing out of the application layer before they reach the transport layer and decrypts inbound packets coming out of the transport layer before they reach the application layer.

Front 283

IP Security Protocol (IPSEC)

Back 283

Sits between IP at the network layer and TCP/UDP at the transport layer. It is done using IKE

Front 284

Internet Key Exchange

Back 284

Both parties generate a random key and send it to the other using an encrypted authenticated PKI process and then put these two numbers together to produce the key.

Front 285

Authentication

Back 285

Passwords, access cards, biometrics

Front 286

Intrusion Prevention Systems

Back 286

designed to detect an intrusion and take action to stop it.

Front 287

carrier sense multiple access with collision avoidance (CSMA/CA)

Back 287

computers listen before they transmit and if no one else is transmitting, they proceed with transmission. wifi

Front 288

carrier sense multiple access with collision detection (CSMA/CD)

Back 288

ethernet uses a contention based media access control technique called CSMA/CD. it waits until the circuit is free and then transmits. a device can listen while transmitting. If it detects any signal other than its own, it will send out a jamming signal and assume a collision has occurred. It waits a random period of time before deciding to re-transmit.

Front 289

point coordination function

Back 289

virtual carrier sense method. Any computer wishing to transmit first sends a request to transmit to the AP, to which if the AP is going to let them broadcast replies with a clear to transmit CTS

Front 290

Controlled-access methods provide poorer performance in low-traffic networks
because computers must wait for permission before transmitting rather than just waiting
for an unused time period. However, controlled-access techniques work better in
high-traffic WLANs because without controlled access there are many collisions. Think
of a large class discussion in which the instructor selects who will speak (controlled
access) versus one in which any student can shout out a comment at any time.

Back 290

Controlled-access methods provide poorer performance in low-traffic networks
because computers must wait for permission before transmitting rather than just waiting
for an unused time period. However, controlled-access techniques work better in
high-traffic WLANs because without controlled access there are many collisions. Think
of a large class discussion in which the instructor selects who will speak (controlled
access) versus one in which any student can shout out a comment at any time.

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WEP

Back 291

With
WEP, the AP requires the user to have a key in order to communicate with it. All data
sent to and from the AP is encrypted so that it can only be understood by computers
or devices that have the key (encryption is discussed in more detail in Chapter 10). If a computer does not have the correct WEP key, it cannot understand any messages
transmitted by the access point and the access point will not accept any data that is not
encrypted with the correct key

Front 292

With Extensible Authentication Protocol (EAP), the WEP keys are produced
dynamically, much like the way in which a DHCP server is used to dynamically produce
IP addresses.

Back 292

With Extensible Authentication Protocol (EAP), the WEP keys are produced
dynamically, much like the way in which a DHCP server is used to dynamically produce
IP addresses.

Front 293

WPA

Back 293

WPA
works in ways similar to WEP and EAP: every frame is encrypted using a key, and the
key can be fixed in the AP like WEP or can be assigned dynamically as users login like
EAP.

Key is changed with every frame.

Front 294

802.11i

Back 294

WPA2 It uses EAP to obtain a master key—in other words, the user logs in to a login
server to obtain the master key. Armed with this master key, the user’s computer and
the AP negotiate a new key that will be used for this session until the users leaves the
WLAN. 802.11i uses the Advanced Encryption Standard (AES) discussed in Chapter 10
as its encryption method.