Switch And Router Configuration

Front 1

Cisco 2960 Switches

Back 1

2960 switches are marketed as low-cost closet switches for enterprise. They are normally access switches.

Front 2

SYST LED

Back 2

Implies the overall system status:

Green - the switch is powered and operational
Amber - the switch's POST process failed, and the IOS did not load

Front 3

RPS LED

(Redundant Power Supply)

Back 3

Indicates the status of extra (redundant) power supply

Front 4

STAT LED

(Status)

Back 4

If on (green), implies that each port LED implies that port's status

Front 5

DUPLX LED

(Duplex)

Back 5

If on (green), each port LED implies that port's duplex (on/green is full; off means half)

Front 6

SPEED LED

Back 6

If on (green), each port LED implies the speed of that port, as follows:

- off means 10 Mbps
- solid green means 100 Mbps
- flashing green means 1 Gbps

Front 7

POST

Back 7

Power On-Self Test -

Tests the hardware in the device. Loaded from ROM

Front 8

Does a switch need an IP address for Telnet to work?

Back 8

Yes. It has to be able to send and receive packets.

Front 9

SSH

Back 9

Secure Shell. Similar to Telnet, but the packets are encrypted, so it is more secure.

SSH uses public key cryptography to exchange a shard session key. SSH requires at least a password and username.

Front 10

Port number for SSH

Back 10

Port 23.

Front 11

How many Telnet (or SSH) sessions can a switch support?

Back 11

16. They are numbered VTY 0 - 15

Front 12

VTY

Back 12

Virtual Terminal Lines. Used for telnet or SSH sessions.

Front 13

User EXEC Mode

Back 13

Allows a user to look access some basic information, but not change the device's operating parameters.

Designated by a ">" at the command prompt.

Front 14

Privileged EXEC mode

(Enable Mode)

Back 14

Allows a user to view more advanced information, and allows the execution of more advanced commands.

Designated by a "#" at the command prompt.

Front 15

Configuration mode

Back 15

Configuration mode accepts configuration commands and is used to determine the operation of the device.

From configuration mode, a user can also enter interface configuration modes and control the operation of specific interfaces.

This mode is designated by "DeviceName(Config)"

Front 16

RAM

(DRAM)

Back 16

Random Access Memory (or dynamic Access Memory).

Used to store the active configuration and tables during device operation. Data in RAM is not maintained when the device is powered off.

Front 17

ROM

Back 17

Read-Only Memory. Static memory that cannot be changed without replacing the physical chips.

ROM stores the POST, Bootstrap, and Diagnostic programs.

Front 18

Flash Memory

Back 18

Flash Memory is re-writable ROM. It is used to store the IOS images - but can store other types of files or backups as well. Does not lose its information if the switch loses power or is reloaded.

Front 19

NVRAM

Back 19

Nonvolatile RAM. Sores the initial or startup configuration file that is used when the device is first powered on. Does not lose its information if the device loses power or is reloaded.

Front 20

COPY Commands

Back 20

The Copy command is used to replace the file in one location with one from another. The copy command always replaces the existing file when the file is copied into NVRAM or into a TFTP server.

copy {tftp | running-config | startup-config} {tftp | running-config | startup-config}

The SOURCE is the first parameter and the DESTINATION is the second parameter.

Front 21

Can users telnet into a switch or router to preform initial configuration?

Back 21

No. The device requires a VTY password for telnet or SSH to function.

Front 22

What ctrl key will take you all the way from config mode to enable mode?

Back 22

Ctrl + Z

Front 23

What does a device require to allow SSH connections?

Back 23

SSH requires that a username and password both be set

Front 24

How are SSH user authenticated?

Back 24

There are two ways SSH is authenticated. The first is to have the username and password configured on the device.

The second is to use an AAA Server (Authentication, Authorization, and Accounting)

Front 25

AAA Server

Back 25

Authentication, Authorization, and Accounting Server.

Used to authenticated SSH Connections to devices. It is an external server.

Front 26

Command for the switch to support both Telnet and SSH

Back 26

transport input telnet ssh

(default omits the ssh)

Front 27

Command to generate matched encryption keys

(used for SSH)

Back 27

crypto key generate rsa

Front 28

Once SSH has been configured on a device, a SSH session can immediately begin?

(True or False)

Back 28

False. Once the SSH is configured on the device, both clients need a copy of the encryption key.

Front 29

What is the command to view a generated public key?

(SSH Encryption)

Back 29

show crypto key mypubkey rsa

Hint 29

Each SSH client needs a cipy of the this key, either by adding this key to the SSH client's configuration beforehand, or letting the switch send this public key to the client when the SSH client first connects to the switch.

Front 30

What is the command to disable Telnet access?

(and only allow SSH)

Back 30

transport input ssh

When the Telnet component is left out of the command, it is disabled.

Front 31

What is the command to enable encryption on ALL usernames and passwords on a device?

Back 31

service password-encryption

With this command, all current usernames and passwords are encrypted, along with all future ones.

Hint 31

This covers the console and VTY passwords.

The passwords are encrypted until the no service password-encryption command is used, at which point existing password remain encrypted, but future passwords will be in clear text

Front 32

MD5

(Message Digest 5)

Back 32

MD5 is the mathematical formula the IOS uses to hide the 'enable secret' password.

MD5 is not actually encryption, rather a type of encoding. It is more secure than other types of encryption used to protect passwords on a device.

Front 33

History Buffer

Back 33

Stores the last commands issued. Users can cycle through the commands using the up arrow.

'show history' will show you the stored commands

Front 34

Default Port Settings for Switches

Back 34

Switches are shipped with ports enabled by default (no shutdown), and set for autonegotiation for ports that operate at multiple speeds. It also auto negotiations whether to go full or half duplex.

Front 35

Where is a Switch's IP Address Configured

Back 35

Switches have their IP addresses configured on the VLAN 1 interface.

Front 36

What is the command to find an IP address when using DHCP on a switch?

Back 36

'show dhcp lease'

This does not work on all switches, as some older models do not support DHCP.

Front 37

What can switches do if they detect an inappropriate device attempting to send frames through the device?

Back 37

When an inappropriate device attempts to send frames to the switch interface, the switch can issue informational messages, discard frames, from that device, or even discard frames from all devices by effective shutting down the interface.

Front 38

What is the command to turn a switch port into an access port?

Back 38

'switchport mode access'

Entered in the interface configuration. Means that the port is only able to access the VLAN, and will not be able to server as a trunking port.

Front 39

What is the command to enable port security?

Back 39

'switchport port-security'

This command can limit the number of MAC addresses that are allowed to access a switch.

Front 40

What is the command to limit the number of MAC addresses that are allowed to access a switch port?

Back 40

'switchport port-security maximum ###number###'

This tells the switch the maximum number of MAC addresses that are allowed to access the port. The default is one MAC address.

This is important so that an attacker cannot unplug a switch from the network, and gain access to the network.

Front 41

What is the command to instruct the port what action to take when it receives a frame from an unauthorized MAC address?

Back 41

'switchport port-security violation {protect | restrict | shutdown}'

The default action is to shutdown the port.

Front 42

What is the command to specify what MAC addresses are allowed to access a port?

Back 42

'switchport port-security mac-address ###'

This command can be issues multiple time to add a multiple allowed MAC addresses.

Front 43

What is the command to instruct a switch to learn the MAC address of the device connected to it, and only allow that device to access the switch?

Back 43

'switchport port-security mac-address sticky'

This tells the switch to learn the MAC address of currently connected devices, and use those addresses to secure access to the port. In other words, the first MAC address heard "sticks" to the configuration so the engineer does not have to know the MAC address of the device connected to the interface ahead of time.

Front 44

Port security can be assigned regardless of the switchport mode assigned to the interface.

(True or false)

Back 44

False. In order for switchport port-security options to be assigned, the port must be in access mode.

You must first enter the 'switchport mode access' command.

Front 45

What command must be entered to allow port security to be active on a port?

Back 45

'switchport port-security' is required to enable port security on an interface.

Front 46

What state is a port placed in when an interface has been disabled due to port security?

Back 46

When a port is disabled for security reasons, it is placed in a secure-shutdown state.

Once it is placed in secure-shutdown state, the interface must be shutdown and brought back up manually in order for the port to be accessible again.

Front 47

What can the port-security configuration tell the ports to do if there is a violation?

Back 47

There are three options for port security when it detects a violation:

1. The interface can be placed into a 'protect' state, where it discards the offending traffic.
2. The interface can be placed into a 'restrict' state where it discards the offending traffic, and sends log and SNMP trap message to the network management station.
3. The interface can be placed in 'shutdown' status where the first two options are implemented, but the port is also shutdown.

Front 48

What does the port-security violation PROTECT do?

Back 48

The 'protect' switchport port-security parameter tells the switch to discard offending traffic when a switch receives frames for a disallowed device.

Front 49

What does the port-security violation RESTRICT do?

Back 49

The 'restrict switchport port-security parameter tells the switch to discard the offending traffic when a switch receives a frame from an unauthorized source. In addition, it generates log files, and sends a SNMP trap message to the network management station.

Front 50

What does the port-security violation SHUTDOWN do?

Back 50

The 'shutdown' switchport port-security parameter tells the switch to shutdown when it receives inappropriate frames from non-allowed MAC addresses. It also sends a SNMP trap message to the network management station.

The shutdown state is referred to as err-disabled (error disabled). In order restore operation to the switch, the port must be shutdown, and then have the 'no shutdown' command issued.

Front 51

What is the default VLAN assignment for switchports?

Back 51

By default, all switchports are assigned to VLAN 1. VLAN 1 cannot be disabled.

Front 52

What is the command to enter configuration range for multiple interfaces at once?

Back 52

'interface range ###'

For example 'interface range f0/1 - 15' would enter a configuration mode that would simultaneously issue commands for interfaces F0/1 through F0/15.

Front 53

What does the 'login' command do in the console or vty configuration modes?

Back 53

It means that a user will be prompted to enter a password when they enter the console or vty.

Front 54

What does the 'password' command do?

Back 54

The 'password' command configures a password a user must enter to gain access to the console or vty. These passwords are stored as plain text by default, although there are options for them to be encrypted.

In order for the password prompt to execute, you must also issue the 'login' command.

Front 55

What does the 'login local' command do?

Back 55

It is used in console and vty configuration mode. It tells the IOS to prompt for a username and password, to be checked against locally configured 'username' global configuration commands on this switch or router.

Front 56

What does the 'username ### password ###' command do?

Back 56

It is a global command, that defines one of possibly multiple usernames and associated passwords, used for user authentication. Used when the 'login local' line configuration command has been used.

Front 57

What does the protocol status in the interface status mean?

(example 'F0/0 is up *line protocol is up* ')

Back 57

The protocol status is the second status code in the interface output. It generally refers to the Layer 2 status.

It is always down if the line status is down. If the line status is up, a protocol status of down usually is caused by mismatched data link layer configuration.

Front 58

What does the line status mean in the interface status output?

(example 'F0/0 *is up*, line protocol is up')

Back 58

The line status is the first status code in the interface information output. It refers to the Layer 1 status.

For example, if a cable is hooked up and the device is powered on.

Front 59

What does 'Administratively down, down' mean in the interface status?

Back 59

The interface has a 'shutdown' command configured on it.

Front 60

What does 'down, down' mean in the interface status?

Back 60

The interface has a 'no shutdown' command configured, but the physical layer has a problem.

For example, no cable has been attached to the interface, or with Ethernet, the switch interface on the other end of the cable is shut down, or the switch is powered off.

Front 61

What does 'up, down' mean in the interface status?

Back 61

Almost always refers to data link layer problems, most often configuration problems.

For example, serial links have this combination when one router was configured to use PPP, and the other defaults to use HDLC.

Front 62

What does the 'up, up' interface status output mean?

Back 62

That the interface is functioning properly.

Front 63

Clocking

Back 63

Clocking is the process by which routers physically slave themselves to the speed dictated by the CSU/DSU.

The CSU/DSU knows the speed, and sends the clock pulses over the cable to the router, and the router reacts to the clocking signal. In effect, the CSU/DSU tells the router when to send the next bit over the cable, and when to receive the next bit, with the touter just blindly reacting to the CSU/DSU for the timing.

Front 64

When should the 'clock rate' command be used?

Back 64

The clock rate command is used in lab or experimental setting. The serial connections are normally between two routers, with one of the acting as the CSU/DSU. These "back to back WAN connections" need one of the devices to supply the clock rate.

This is rarely used in production settings.

Front 65

Clock rate ##speed##

Back 65

The 'clock rate ##speed## ' command is used to set the rate (in bits per second) on the the router that is functioning as the DCE device.

If the device does not have a DCE cable connected to it, and you issue the clock rate command, the IOS will reject the command. There is no error message, it just ignores the input.

Front 66

'Show Controllers' command

Back 66

The 'show controllers' command list many lines of information per interface, or for one interface, for the hardware controller of the interface. On serial interfaces, this command identifies the cable as either a DCE or DTE cable.

Front 67

What does the 'bandwidth ##speed## ' command do?

Back 67

The 'bandwidth ##speed## ' command tells the IOS the speed of the link, in kilobits per second, regardless of whether the router is supplying clocking.

However, this command does no change the actual speed. Instead, the router uses it documentation, and in calculations related to routing, such as EIGRP or OSPF.

Front 68

The bandwidth command must be set on each interface so that the router knows the interface's speed.

(True or false)

Back 68

False. The 'bandwidth' command has nothing to do with the actual speed of the interface. It tells the router instead what to think the speed of the interface is (for use in routing protocols).

If no 'bandwidth' command is set, then the router will use a default value.

Front 69

What is the purpose of the Router's Auxiliary (AUX) Port?

Back 69

The AUX port is used for remote configuration, usually with a modem.

Front 70

ROM Monitor

(ROMMON)

Back 70

ROMMON is a diagnostic mode. It loads from ROM and is designed for disaster recovery when the IOS cannot be located.

Front 71

Configuration Register

Back 71

The configuration register is a special 16-bit number that can be set on any Cisco router. The configuration register's bits control different settings for some low level operating characteristics of the router.

Front 72

What does the 'config-register' global configuration command do?

Back 72

The config-register global config command is used to set the configuration register value, which tells the router which IOS image to load. This command automatically saves the command, you do not need to save the running-config into the startup-config.

The command is entered in hex, so a sample command would be 'config-register 0x2100'.

Front 73

What is the default configuration register setting on most Cisco routers?

Back 73

The default configuration register setting is hexadecimal 2102.

In hex, 0x2102.

Front 74

What is the configuration register setting for ROMMON OS?

Back 74

The configuration register value for ROMMON is 2100.

In hex, 0x2100.

Front 75

What is the command to view a router's routing table?

Back 75

The command to view the routing table is 'show ip route'

Front 76

What does "C" stand for in the 'show ip route' output?

Back 76

The "C" stands for "Connected." This means a network is directly connected to the router.

Front 77

What does the 'terminal ip netmask-format decimal' EXEC command do?

Back 77

The 'terminal ip netmask-format decimal' EXEC command changes the format of the format of the subnet masks displayed in 'show' commands.

Front 78

How does a router issue a 'ping' command?

Back 78

The router pings a destination by sending five "ICMP echo request" packets.

When the destination receives the packet, if it is able to respond, it will do so with a "ICMP echo reply."

Front 79

ICMP echo request

Back 79

The type of packet sent to a destination with the 'ping' command

Front 80

ICMP echo reply

Back 80

The type of packet returned from the destination of a ping back to the source

Front 81

What does "....." mean when pinging a destination?

Back 81

"....." means that the destination was not reachable. A " . " means failure of a ping. The attempt is considered a failure if a response is not received in 2 seconds.

Front 82

What does "!!!!!" mean when pinging a destination?

Back 82

"!!!!!" means that the ping was successful in communicating with the destination. " ! " means a ping is successful.

Front 83

What does "S" mean in the show ip route output?

Back 83

"S" means that a route is statically configured.

Front 84

Once a route is statically given, it is automatically added to the routing table?

(True or False)

Back 84

False. For the route to be added to the routing table, the outgoing interface implied by the next-hop route IP address must be in an "up and up" state.

Front 85

What is the command to add a static route?

Back 85

To add a static route, you need to be in the configure terminal mode. The command is 'ip route ##destination network## ##subnet mask## ##next hop address or exit interface## '

Front 86

When configuring a static route, you can specify an exit interface instead of a next hop address.

(True or False)

Back 86

True. You can configure all traffic for a specific network to leave via a designated interface instead of a next-hop address.

Front 87

What is the purpose of the extended 'ping' command?

Back 87

The extended 'ping' command allows the route to more closely resemble a 'ping' issued by end users on other machines. With the extended ping, you can change the apparent source IP address used for the ICMP echo request sent by the command.

In a real network, when a ping from a router works, but a ping from a host does not, the extended ping could help you re-create the problem without needing to work with the end user on the phone.

The extended ping source source address can only be an interface on the router.

Front 88

What is a default route?

Back 88

The default route is a route that matches all networks. It is used when there is no clear path to a network, and is known as the "route of last resort."

The default route typically has an address of 0.0.0.0 0.0.0.0 so it matches all networks.

The default route is identified in the routing table with an * .

Front 89

What is RIP?

Back 89

RIP is a distance vector protocol that measures various routes in the metric of hope counts. RIP continually sends out routing updates every 30 seconds by default.

Each router receives updates on the paths through the network, and selects the best one based on the distance in hops to each destination.

Front 90

Interior Gateway Protocol (IGP)

Back 90

An Interior Gateway Protocol (IGP) is a routing protocol that was designed and intended for use inside a single autonomous system.

Front 91

Exterior Gateway Protocol (EGP)

Back 91

An Exterior Gateway Protocol (EGP) is a routing protocol that was designed and intended for use between different autonomous systems.

Front 92

Autonomous System

Back 92

An Autonomous System is an internetwork under the administrative control of a single organization.

Front 93

Border Gateway Protocol (BGP)

Back 93

A Border Gateway Protocol (BGP) is used to exchange routers between routers in different autonomous systems, and is the only EGP widely used today.

Front 94

Autonomous System Number (ASN)

Back 94

An Autonomous System Number (ASN) is the number assigned to each autonomous system. It is assigned by ICANN.

Each organization needs a unique ASN so BGPs can ensure that packets do not loop around the global internet by making sure that packets do not pass through the same autonomous system twice.

Front 95

Metrics

Back 95

Routing protocols must have some way to decide which route is best when a router learns of multiple routes to reach a subnet. The metric give numeric value to each route. The lower the metric, the better the route.

Front 96

Routers preform best by having the largest number of routes in a routing table, so they can pick the best one.

(True or False)

Back 96

False. Router preform best with smaller routing tables. Only the best routes are added to a table.

Front 97

Why is Route Summarization important?

Back 97

Route Summarization helps to shorten the routing table while retaining all the needed routes in the network.

Front 98

Why is Manual Summarization generally better than autosummarization?

Back 98

Manual Summarization give the network engineer a great deal of control and flexibility, allowing the engineer to choose what summary routes to advertise, instead of just being able to summarize with a classful network.

Front 99

Classful Routing Protocols

Back 99

Classful Routing Protocols must consider class rules. They do not support VLSM or Manual Route summarization.

They do not send subnet masks in their routing updates.

Front 100

Classless Routing Protocols

Back 100

Classless Routing Protocols do not need to consider class rules. They do support VLSM, and manual route summarization. They send subnet mask information in their routing updates.

Front 101

Convergence

Back 101

Convergence refers to the overall process that occurs with routing protocols when something changes in a network topology. Convergence is used by routing protocols to recognize the changes, to figure out the new best routes to each subnet, and to change all the router's routing tables.

Front 102

RIP-1 is a classless protocol?

(True or False)

Back 102

False. RIP-1 is a classful protocol.

Front 103

RIP-1 supports VLSM?

(True or False)

Back 103

False. RIP-1 is a classful protocol that does not support VLSM.

Front 104

RIP-1 sends its mask in update?

(True or False)

Back 104

False. RIP-1 is a classful protocol, so the mask is unneeded.

Front 105

RIP-1 is a distance vector protocol?

(True or False)

Back 105

True. RIP-1 is a distance routing protocol that uses hop count as the metric.

Front 106

RIP-1 is a link-state protocol?

(True or False)

Back 106

False. RIP-1 is a distance vector protocol.

Front 107

RIP-1 does not support autosummarization?


(True or False)

Back 107

False. RIP-1 does support autosummarization.

Front 108

RIP-1 supports manual summarization?

(True or False)

Back 108

False. RIP-1 does not support manual route summarization.

Front 109

RIP-1 is a proprietary Cisco protocol?

Back 109

False. RIP-1 is not Cisco proprietary.

Front 110

RIP-1 sends routing updates to a multicast IP address?

(True or False)

Back 110

False. RIP-1 does not send routing updates to a multicast IP address.

Front 111

RIP-1 supports authentication.

(True or False)

Back 111

False. RIP-1 does not support authentication.

Front 112

RIP-1 has fast convergence.

(True or False)

Back 112

False. RIP-1 is slow at converging networks.

Front 113

RIP-2 is a classless routing protocol.

(True or False)

Back 113

True. RIP-2 is a classless routing protocol.

Front 114

RIP-2 supports VLSM.

(True or False)

Back 114

True. RIP-2 is a classless routing protocol, so it does support VLSM.

Front 115

RIP-2 sends masks in its updates.

(True or False)

Back 115

True. RIP-2 does send masks in its updates.

Front 116

RIP-2 is a distance vector protocol.

(True or False)

Back 116

True. RIP-2 is a distance vector protocol. It uses hop-count as the metric to decide the best routes.

Front 117

RIP-2 is a link-state protocol.

(True or False)

Back 117

False. RIP-2 is a distance vector protocol.

Front 118

RIP-2 supports autosummarization.

(True or False)

Back 118

True. RIP-2 does support autosummarization.

Front 119

RIP-2 supports manual route summarization.

(True or False)

Back 119

True. RIP-2 does support manual summarization.

Front 120

RIP-2 is a proprietary Cisco protocol.

(True or False)

Back 120

False. RIP-2 is not proprietary.

Front 121

RIP-2 sends its routing updates to a multicast IP address.

(True or False)

Back 121

True. RIP-2 does send its routing updates to a multicast IP address.

Front 122

RIP-2 supports authentication.

(True or False)

Back 122

True. RIP-2 does support authentication.

Front 123

RIP-2 is a fast converging protocol.

(True or False)

Back 123

False. RIP-2 converges very slowly. This is a major downside of the protocol.

Front 124

EIGRP is a classless protocol.

(True or False)

Back 124

True. EIGRP is a classless protocol.

Front 125

EIGRP supports VLSM.

(True or False)

Back 125

True. EIGRP does support VLSM.

Front 126

EIGRP sends its mask in its updates.

(True or False)

Back 126

True. EIGRP does send its mask in updates.

Front 127

EIGRP is a distance vector protocol.

(True or False)

Back 127

False. (Sort of). EIGRP is a hybrid protocol, that does consider distance, but not as its sole consideration.

EIGRP also has link-state characteristics. EIGRP is often referred to as an Advanced Distance Vector protocol.

Front 128

EIGRP is a Link-State routing protocol.

(True or False)

Back 128

False. (Sort of). EIGRP is a hybrid protocol, that does have some link state elements, but also elements of a distance vector protocol.

EIGRP is often referred to as an Advanced Distance Vector protocol.

Front 129

EIGRP supports autosummarization.

(True or False)

Back 129

True. EIGRP does support autosummarization.

Front 130

EIGRP supports manual summarization.

(True or False)

Back 130

True. EIGRP does support manual route summarization.

Front 131

EIGRP is a Cisco proprietary protocol.

(True or False)

Back 131

True. EIGRP is a Cisco proprietary protocol.

Front 132

EIGRP sends routing updates to a multicast IP address.

(True or False)

Back 132

True. EIGRP does send its routing updates to a multicast IP address.

Front 133

EIGRP supports authentication.

(True or False)

Back 133

True. EIGRP does support authentication.

Front 134

EIGRP is a very slow converging protocol.

(True or False)

Back 134

False. EIGRP is a very fast converging protocol.

Front 135

OSPF is a classless routing protocol.

(True or False)

Back 135

True. OSPF is a classless routing protocol.

Front 136

OSPF supports VLSM.

(True or False)

Back 136

True. As a classless protocol, OSPF does support VLSM.

Front 137

OSPF sends mask in updates.

(True or False)

Back 137

True. As a classless protocol, OSPF does send masks in their updates.

Front 138

OSPF is a distance vector protocol.

(True or False)

Back 138

False. OSPF is a link-state protocol.

Front 139

OSPF is a link-state protocol.

(True or False)

Back 139

True. OSPF is a link-state protocol.

Front 140

OSPF supports autosummarization.

(True or False)

Back 140

False. OSPF does not support autosummarization.

Front 141

OSPF supports manual summarization.

(True or False)

Back 141

True. OSPF does support manual summarization.

Front 142

OSPF is a Cisco proprietary protocol.

(True or False)

Back 142

False. OSPF is not proprietary.

Front 143

OSPF sends routing updates to a multicast IP address.

(True or False)

Back 143

True. OSPF does send its updates to a multicast IP address.

Front 144

OSPF does support authentication.

(True or False)

Back 144

True. OSPF does support authentication.

Front 145

OSPF is a fast converging protocol.

(True or False)

Back 145

True. OSPF is a fast converging protocol.

Front 146

IS-IS is a classless protocol.

(True or False)

Back 146

True. IS-IS is a classless routing protocol.

Front 147

IS-IS supports VLSM.

(True or False)

Back 147

True. IS-IS does support VLSM.

Front 148

IS-IS sends mask in update.

(True or False)

Back 148

True. IS-IS does send its mask in update.

Front 149

IS-IS is a distance vector protocol.

(True or False)

Back 149

False. IS-IS is a link-state protocol.

Front 150

IS-IS is a link-state protocol.

(True or False)

Back 150

True. IS-IS is a link-state protocol.

Front 151

IS-IS supports autosummarization.

(True or False)

Back 151

False. IS-IS does not support autosummarization.

Front 152

IS-IS supports manual summarization.

(True or False)

Back 152

True. IS-IS does support manual summarization.

Front 153

IS-IS is a proprietary Cisco protocol.

(True or False)

Back 153

False. IS-IS is not a proprietary protocol.

Front 154

IS-IS sends updates to a multicast IP address.

(True or False)

Back 154

Not Applicable to IS-IS.

Front 155

IS-IS supports authentication.

(True or False)

Back 155

True. IS-IS does support authentication.

Front 156

IS-IS is a fast converging protocol.

(True or False)

Back 156

True. IS-IS is a fast converging protocol.

Front 157

RIP sends multicast routing updates to which reserved IP multicast IP address?

Back 157

RIP sends multicast routing updates to multicast IP address 224.0.0.9.

Front 158

What is the terminal configuration command to enter RIP configuration mode?

Back 158

'R(config)# router rip' will enter router configuration for RIP.

Front 159

What is the command for a router to use the RIP-2 protocol?

Back 159

In router rip configuration, use the 'version 2' command.

R(config)#router rip
R(config-router)# version 2

Front 160

RIP can be configured on only some of the interfaces assigned to a single network.

(True or False)

Back 160

False. There is no way to configure RIP to only work on some interfaces within the same network.

It is however possible to set an interface to be passive so that it stops the sending out RIP updates on the interface.

Front 161

What is the command to stop an interface from sending out RIP updates?

Back 161

'passive-interface ## ' will set the interface into passive mode, which will stop it from sending out any RIP updates.

Front 162

RIP will only store routes for a classful network.

(True or False)

Back 162

True. RIP will accept commands for other networks, but will actually store the routes for the single classful network.

Example: the command 'network 10.1.2.3' would be accepted by the router, but the network 10.0.0.0 would actually be stored.

Front 163

What is the command to tell RIP which networks to advertise?

Back 163

'R(config-router)# network 10.0.0.0'

Front 164

What is the command to view the RIP routes in the routing table?

Back 164

'show ip route rip'

Front 165

What is the command to view the router's IP protocols?

Back 165

'show ip protocols'

Front 166

What is the administrative distance?

Back 166

When a router has more than one possible route to a destination, it use the administrative distance to judge how "good" a route is.

The better the route is, the lower its AD. The routes with the lowest AD are the ones that are added to the routing table.

Front 167

What is the administrative distance for connected routes?

Back 167

Connected routes have an administrative distance on 0

Front 168

What is the administrative distance for static routes?

Back 168

Static routes have an administrative distance of 1.

Front 169

What is the administrative distance for EIGRP.

Back 169

EIGRP has an administrative distances of 90.

Front 170

What is the administrative distance for IGRP?

Back 170

IGRP has an administrative distance of 100

Front 171

What is the administrative distance for OSPF?

Back 171

OSPF has an administrative distance of 110.

Front 172

What is the administrative distance for IS-IS?

Back 172

IS-IS has an administrative distance of 115.

Front 173

What is the administrative distance for RIP?

Back 173

RIP has an administrative distance of 120.

Front 174

Backup Static Route

Back 174

A backup static route is a defined route, but is intended to be a backup route. However, as a static route, its administrative distance would be lower than all routing protocol routes.

In these situations, you can configure the AD to be higher than the routes from the routing protocols, so that they will be a backup, and only be used in the routes from the protocols go down.

Front 175

What is the command to have the router generate timestamps?

Back 175

'service timestamps' global configuration

Front 176

What happens when an IP destination matches more than one route in a routing table?

Back 176

When a destination IP address matches more than one route in a routing table, the router chooses the most direct route.

It looks for the route that has the longest prefix, which it determines is the most direct route.

Front 177

What is the command to view detailed information on the route a packet will travel to a specific IP address?

Back 177

'show ip route ##ip address## ' will show the route a packet will take from the router to the specified IP address.

The output will shot how the route was learned, the distance, and metric. It will show when the route was last broadcast, and interface on which the packet will leave.

Front 178

What information does a host learn through DHCP?

Back 178

Using DHCP a host will learn:
- the host IP address
- the associated subnet mask
- the IP address of the default gateway
- the IP address of the DNS server

Front 179

What is the command to enter a sub-interface on a router to configure a router to work with VLANs?

Back 179

To enter a sub-interface, you type the interface name and number, and then a decimal followed by the number of the vlan.

For example: Fa0/1.2 to configure Fa0/1 to work with VLAN 2.

Front 180

Routing Protocol

Back 180

A routing protocol is a set of messages, rules, and algorithms used by routers for the overall purpose of learning routes.

Each router chooses the best route to each subnet (path selection) and finally places those best routes in its IP routing table.

Front 181

Routed Protocol

Back 181

A routed protocol refers to a protocol that defines packet structure and logical addressing, allowing routers to forward or route the packets.

IP is an example of a routed protocol.

Front 182

Routing protocol algorithms

Back 182

The term routing protocol algorithms refers to the logic and processes used by different routing protocols to learn all routes, choose the best route to each subnet, and converge in reaction to changes in the internetwork.

Front 183

OSPF is much easier to deploy than RIP.

(True or false)

Back 183

False. OSPF requires more planning, especially in medium to large networks.

Front 184

What metric does OSPF use?

Back 184

OSPF uses Cost as its metric, which is the sum of all interface cost settings for all links in a route, with the cost defaulting to be based on interface bandwidth.

Front 185

How does EIGRP find a metric?

Back 185

The EIGRP metric is a calculated based on the route's slowest link and the cumulative delay associated with each interface in the route.

Front 186

You can change the speed of an interface by using the 'bandwidth' command.

(True or false)

Back 186

False. The bandwidth command does not change the actual physical speed of the interface. It just tells the IOS what speed to assume the interface is using.

Front 187

How often does RIP-2 send periodic updates (by default)?

Back 187

RIP-2 sends out its periodic updates every 30 seconds by default.

Front 188

RIP-2 sends out full routing updates.

(True or false)

Back 188

True. RIP-2 sends out full updates.

Front 189

OSPF sends out periodic updates.

(True or false)

Back 189

False. OSPF does not send out periodic updates.

Front 190

EIGRP sends out periodic updates.

(True or false)

Back 190

False. EIGRP does not send out periodic updates.

Front 191

Which routing protocol supports unequal-cost load balancing?

Back 191

EIGRP supports unequal-cost load balancing.

Front 192

What is the administrative distance for BGP (external routes)?

Back 192

The administrative distance for BGP (for external routes) is 20.

Front 193

Through its periodic updates, RIP learns everything about the networks it communicates with.

(True or false)

Back 193

False. A RIP only knows the measure of distance (the metric), and the next-hop router and outgoing interface to use for that route (a vector, or direction).

Front 194

Routing Loops

Back 194

Routing Loops occur when the routers forward packets such that the same single packet ends up back at the same routers repeatedly, wasting bandwidth and never delivering the packet.

Front 195

Route Poisoning

Back 195

When a route fails, distance vector routing protocols risk causing routing loops until every router in the internetwork believes and knows that the original route has failed.

Route poisoning refers to the practice of advertising a route, but with a special metric value called infinity. Simply put, routers consider routes advertised with an infinite metric to have failed.

Front 196

What does it mean when a route has a value of infinity?

Back 196

When a route has a value of infinity, it means that the route has failed.

Each protocol has a different value for infinity.

Front 197

What value does RIP use for infinity, to signal that a route is down?

Back 197

RIP uses the value 16 as infinity to signal that a route is down.

Front 198

Counting to Infinity Process with RIP

Back 198

Distance vector protocols experience a problem called counting to infinity. This happens when a route fails, and is marked as a bad route, but the routers keep advertising routes back to each other, and they keep being updated.

Eventually, they will all get the bad route as marked as infinite, but it can take several minutes. During that time, network performance can be severely degraded, and users might think the network went down.

Front 199

Split Horizon

Back 199

In routing updates sent out interface X, do not include routing information about routes that refer to interface X as the outgoing interface.

More simply, split horizon means what when router 1 learns a route from router 2, 1 has no need to advertise that same route back to the router 2.

Front 200

How do RIP protocols attack the counting to infinity problem?

Back 200

Distance vector protocols attack the counting to infinity problem by ensuring that every router learns that the route has failed, through every means possible, as quickly as possible. It does this by using triggered updates, and poison reverse.

Front 201

Triggered update

Back 201

When a route fails, distance vectors do not wait for the next periodic update, instead they send an immediate triggered update listing the poisoned route.

Front 202

Poison reverse

Back 202

With distance vectors, when learning of a failed route, they suspend split horizon rules for that route and advertise a poisoned route.

Front 203

Holddown Process

Back 203

Holddown prevent the looping and counting to infinity problem in distance vectors. The holddown process tells a router to ignore new information about the failed route for a time period called the holddown time, as counted using the holddown timer.

After hearing a poisoned route, it starts a holddown timer for that one route. Until the timer expires, it does not believe any other routing information about the failed route, because believing that information may cause a routing look.

However, information learned from the neighbor that originally advertised the working rotue can be believed before the holddown timer expires.

Front 204

What does OSPF stand for?

Back 204

OSPF stands for Open Shortest Path First.

Front 205

What is the LSDB?

Back 205

LSDB stands for Link State Database. This is stored in RAM, and contains information about every device in the internetwork.

The LSDB contains information about not only the up and working routes and interfaces and links, but all routers and interfaces and links, even if the interfaces are down.

Front 206

What is a LSA?

Back 206

LSA stands for Link State Advertisements. Routers send out updates containing information about the routers and the links (subnets) attached to the routers.

Front 207

Router LSA

Back 207

The Router LSA includes a number to identify the router (router ID), the router's interface IP addresses and masks, the state (up or down) of each interface, and the cost (metric) associated with the interface.

Front 208

Link LSA

Back 208

The Link LSA identifies each link (subnet) and the routers that are attached to that link. It also identifies the link's state (up or down).

Front 209

Routers flood LSAs to every device on the network (with OSPF).

(True or false)

Back 209

False. The router first asks its neighbor if already knows about the LSA. If it does, it responds, and the LSA will not be sent.

Front 210

OSPF floods LSAs every 30 seconds (by default).

(True or false)

Back 210

False. OSPF floods LSA every 30 minutes by default.

Front 211

If the LSA changes, the router immediately floods the changed LSA.

(True or false)

Back 211

True. If links go down, or LSAs otherwise change, then the router immediately floods out the new LSAs.

Front 212

Dijkstra SPF (shortest path first)

Back 212

Dijkstra SPF is an algorithm that defines how a router should process the LSDB, with each router considering itself to be the starting point for the route. Each router uses itself as the starting point because each router needs to put routes in its own routing table.

The SPF algorithm calculates all the possible routes to reach a subnet, and the cumulative metric for each entire route, for each possible destination subnet. In short, each router must view itself as the starting point, and each subnet as the destination, and use the SPF algorithm to look at the LSDB road map to find and pick the best route to each subnet.

Front 213

How does SPF find the best route in OSPF?

Back 213

The SPF algorithm adds the cost associated with each link between itself and the destination subnet over each possible route.

The costs used by the algorithm can be calculated, or entered manually on each router.

Front 214

What happens in OSPF when a link goes down?

Back 214

When a link goes down in OSPF, LSAs are immediately flooded out that reflect the current state of the internetwork. New routes are calculated based on the new information, and replace the down routes with new ones.

Front 215

Link-State Protocols consume much less CPU and RAM than Distance Vector protocols.

(True or false)

Back 215

False. Link-state protocols use more processing power, but with proper planning this disadvantage can be reduced.

Front 216

OSPF Neighbor

Back 216

An OSPF neighbor is a router that connects to the same date link with which the first router can and should exchange routing information using OSPF.

Front 217

What is the command to view OSPF neighbors?

Back 217

'show ip ospf neighbor' will show the neighbor table

Front 218

What is the command to see the OSPF LSDB?

Back 218

'show ip ospf database' will display the LSDB

Front 219

OSPF Hello Process

Back 219

The OSPF Hello process defines how neighbors can be dynamically discovered, which means that new routers can be added to a network without requiring every router to be reconfigured.

To discover other OSPF speaking routers, a router sends multicast OSPF Hello packets to each interface and hopes to receive OSPF hello packets from other routers connected to those interfaces.

Front 220

What information is in the OSPF Hello message?

Back 220

OSPF Hello messages list each router's Router ID (RID), which serves as each router's unique name or identifier for OSPF.

The Hello message includes the sending router's RID, Area ID, Hello interval, dead interval, router priority, the RID of the designated router, the RID of the backup designated router, and a list of neighbors that the sending router already knows about on the subnet,

The Hello message follows the IP packet header, with IP packet protocol type 89.

Front 221

OSPF Router ID (RID)

Back 221

OSPF needs to uniquely identify each router, so OSPF uses a concept called the OSPF router ID (RID).

RIDs are 32-bit numbers written in dotted decimal, so using an IP address is a convenient way to find a default RID. Or the RID can be directly configured.

Front 222

What multicast IP address is used for OSPF broadcasts?

Back 222

224.0.0.5 is the multicast ip address intended for all OSPF speaking routers.

Front 223

How does OSPF know two way communication has been established with a neighbor?

Back 223

During the Hello process, routers exchange information about the neighbors each router already knows about. Once a router sees its own RID in a received Hello, the router believes that two way communication has been established with that neighbor.

Once a two-way state has been established, more detailed information, such as LSAs ca be exchanged.

Front 224

What can stop routers on the same subnet from becoming neighbors in OSPF?

Back 224

Routers on the same subnet must agree about several of the parameters exchanged in the Hello; otherwise, the routers simply do not become neighbors.

These parameters include:
-subnet mask used on the subnet
-subnet number (as derived using the subnet mask and each router's interface IP address)
-Hello interval
-Dead interval
-OSPF area ID
-Must pass authentication checks (if used)
-Value of the stub area flag

If any one of these parameters differs, the routers do not become neighbors.

Front 225

OSPF Hello interval

Back 225

OSPF routers send Hello messages every Hello Interval. This lets its neighbors know that the router is still up. If the router fails to issue a Hello message within a set amount of time (Dead Interval), its neighbors will assume it is down and reconverge the network.

The default Hello Interval for Ethernet is 10 seconds.

Front 226

OSPF Dead Interval

Back 226

The Dead Interval is the time defined so that if a router no longer hears a Hello from a neighbor, the router believes the neighbor is no longer reachable, and the router reacts and reconverges the network.

In Ethernet, the default Dead Interval is 4 times the Hello Interval (or 40 seconds).

Front 227

What does OSPF Neighbor States refer to?

Back 227

An OSPF neighbor state is the router's perception of how much work has been completed in the normal processes done by two neighboring routers.

Front 228

OSPF Init State

Back 228

OSPF Init state means that the neighbor relationship is being initialized.

Front 229

What does OSPF "seen [null]" mean?

Back 229

OSPF "seen [null]" means that the router has not yet seen any approved potential neighbors.

Front 230

An OSPF Router only has limited information about the network, mainly limited to the next hop addresses.

(True or False)

Back 230

False. An OSPF LSDB has information on the entire network. Each router exchange the contents of their LSDBs until each router has an exact copy.

Front 231

All OSPF internetworks must have both a DR and BDR.

(True or False)

Back 231

False. The routers must decide if they should directly exchange the topology information directly, of if they should learn it indirectly.

A DR is not required on Point to Point subnetworks.

Front 232

OSPF Designated Router (DR)

Back 232

OSPF can have Designated Router (DR) that is responsible to making sure all device have a copy of the network topology. To minimize traffic, the devices will elect one router to be responsible for sending the information out, so that each device does not duplicate the effort.

Front 233

OSPF Backup Designated Router (BDR)

Back 233

The Backup Designated Router (BDR) is the router designated as the backup in case the DR goes down. If it does, the BDR takes over as DR.

Front 234

Point to Point OSPF network

Back 234

OSPF Point to Point networks are between two router on a subnet.

Front 235

Broadcast OSPF network

Back 235

An OSPF Broadcast network is for use on data links that support broadcast frames, such as LANs.

Front 236

How is the DR selected in OSPF?

Back 236

When a DR is needed in OSPF, the routers on the network hold an election. The router with the highest OSPF Priority Setting becomes the DR.

If there are two devices with the same OSPF priority setting, then the device with the highest RID wins. The second highest device becomes the BDR.

Front 237

In OSPF, when a new device is connected that has a higher OSPF priority setting than the current DR, it automatically becomes the new DR.

(True or False)

Back 237

False. Once the DR is elected, a new device with a higher value will not supersede it.

Front 238

OSPF Full Neighbor State

(Fully Adjacent)

Back 238

The OSPF Full Neighbor state means that both routers know the exact same LSDB details, and are fully adjacent.

Front 239

How often are LSAs reflooded in an OSPF network?

(assuming the network is fully functioning, and using default settings)

Back 239

LSAs are reflooded every 30 minutes by default. The timer is based on each LSA, so there is no single moment when OSPF sends a lot of messages to reflood all LSAs. Each LSA is reflooded by the router that created it.

Front 240

How does OSPF choose the least cost route between two locations?

Back 240

Each router uses SPF to analyse the database and select the best route. It chooses the best route based on the cost of the interface.

Each interface has an OSPF cost associated with it. The router looks at each possible route, adds up the costs on the interfaces out which packets would be forwarded on that route, and then picks the least cost route.

Front 241

OSPF works well in all networks, regardless of size.

(True or False)

Back 241

False. (sort of). In large networks, engineers need to think about and plan how to use several OSPF features that allow it to scale well.

Since SPF analyses all of the paths through the network, the sheer amount of processing required to run the complex SPF algorithm might cause convergence time to be slow and the routers might experience memory shortages in larger networks.

Front 242

OSPF Areas

Back 242

OSPF areas break up the network so that routers in one area know less topology information about the subnets in the other area - and they do not know about the routers in the other area at all. This saves processing and memory, so that each device does not need to calculate routes to every device, making it much more efficient in large network.

Front 243

OSPF Area Border Router (ABR)

Back 243

The Area Border Router (ABR) is on the border between two different areas. It has interfaces connected to the backbone area and to at least one other area.

Front 244

OSPF Autonomous System Border Router (ASBR)

Back 244

An OSPF Autonomous System Border Router that connects to routers that do not use OSPF for the purpose of exchanging external routes into and out of the OSPF domain.

Front 245

OSPF Backbone Area

Back 245

The OSPF Backbone Area is a special area to which all other areas must connect - Area 0.

Front 246

OSPF Backbone Router

Back 246

An OSPF Backbone Router is a router in one area, the backbone area.

Front 247

OSPF Internal Router

Back 247

An OSPF Internal Router is in a single nonbackbone area.

Front 248

OSPF External Route

Back 248

An OSPF external route is a route learned from outside of the OSPF domain and then advertised into the OSPF domain.

Front 249

OSPF Intra-area Route

Back 249

An OSPF Intra-Area Route is a route to a subnet inside the same area as the router.

Front 250

OSPF Interarea Route

Back 250

An OSPF Interarea Route is a route to a subnet in an area of which the router is not a part.

Front 251

OSPF Autonomous System

Back 251

An OSPF Autonomous System is a reference to a set of routers that use OSPF.

Front 252

What are the key advantages to using OSPF Areas?

Back 252

Using OSPF areas has many advantages:
- The smaller per area LSDB requires less memory
- The router requires fewer CPU cycles to process the smaller per area LSDB with the SPF algorithm, reducing CPU overhead and improving convergence time.
- The SPF algorithm has to be run on internal routers only when an LSA inside the area changes so routers have to run SPF less often.
- Less information must be advertised between areas, reducing bandwidth required to send LSAs.
- Manual summarization can only be configured on ABRs and ASBRs, so areas allow for smaller IP routing tables by allowing for the configuration of manual route summarization.

Front 253

What is the command to enter the OSPF configuration mode?

Back 253

The command to enter OSPF configuration mode is 'router ospf ##process id## '

Front 254

What is the command to configure the OSPF Router ID?

Back 254

The command to configure the OSPF Router ID is 'router-id ##id value## '

Front 255

What is the command to configure a network in OSPF?

Back 255

In the OSPF Router Configuration, the command to add a network is 'network ##ip address## ##wildcard-mask## area ##area id## '

Front 256

What is the OSPF command to change the Hello or Dead intervals?

Back 256

In OSPF, the command to change the Hello Interval is 'ip ospf hello-interval ##time## '.

The command to change the Dead Interval is 'ip ospf dead-interval ##time## '.

Front 257

What is the OSPF Wildcard Mask?

Back 257

The wildcard mask in the OSPF network command works like an ACL wildcard mask, but with the restriction that it must have only one string of consecutive binary 1s and 0s.

For example: 0.0.255.255

Front 258

What does an "O" mean for an OSPF route in the 'show ip route' output?

Back 258

With OSPF routes, an "O" next to the route means that it is intra-area.

Front 259

What does an "IA" mean for an OSPF route in the 'show ip route' output?

Back 259

With OSPF routes, an "IA" next to the route means it is an interarea (IA) route.

Front 260

What is an OSPF loopback interface?

Back 260

An OSPF loopback interface is a virtual interface that can be configured with the 'interface loopback ##interface-number## ' command.

Loopback interfaces do not rely on any hardware, these interfaces can be up/up whenever IOS is running, making them good interfaces on which to base an OSPF RID.

Front 261

How is an OSPF Router ID (RID) chosen?

Back 261

In choosing a RID, OSPF first looks to see if a RID has been configured. If so, then that is used.

Next, the router looks to see if a lookback address has been configured. If so, then the highest value is assigned as the RID.

Finally, a router will use the highest numeric IP address from all interfaces whose interface status code (first status code) is up.

The RID is selected by the router during initialized, which happens during the initial load of the IOS.

Front 262

OSPF Null Authentication

Back 262

OSPF Null Authentication means there is no authentication.

The command is 'ip ospf authentication null'.

Front 263

OSPF Authentication

(Clear Text)

Back 263

OSPF has basic authentication, which uses a simple text password.

The command for this is 'ip ospf authentication'.

The password is set with 'ip ospf authentication-key ##password## '.

Front 264

OSPF MD5 Authentication

Back 264

This OSPF Authentication protects the password with MD5, which is the preferred option.

The command is 'ip ospf authentication message-digest'.

The command to set the password is 'ip ospf message-digest-key ##key number## md5 ##key value## '.

Front 265

What happens in OSPF when authentication is enabled?

Back 265

In OSPF, when authentication is enabled, each router must pass the authentication process for every OSPF message with every neighboring router on that interface.

Front 266

OSPF Load Balancing

Back 266

When the metric is a tie, the router can put up to 16 different equal-cost routes in the routing table (the default is four different routes) based on the setting of the 'maximum- paths ##number## ' subcommand.

A router could load-balance the packets on a per-packet basic. Alternatively, the load balancing could be on a per-destination IP address basis.

Front 267

Which commands display information about the Cisco IOS software version currently running?

Back 267

- 'show running-config'
- 'show version'
- 'show flash'

Front 268

How many simultaneous Telnet sessions does a Cisco router support by default?

Back 268

5

A router supports five simultaneous Telnet sessions by default.

Front 269

What is the command to replace an IOS Image?

Back 269

'copy tftp flash'

This will copy an IOS image from a TFTP server into the device's flash

Front 270

What is the command to backup the current IOS image?

Back 270

'copy flash tftp'

This will copy the image from Flash, and back it up on a TFTP server

Front 271

What is the syntax of a 'copy' command?

Back 271

'copy ##source## ##destination## '

Front 272

At the global configuration prompt, the administrator has just entered the following command on a router that has not been previously configured for RIP:

'RouterA(config)# router rip'

What state is the router now in after executing the command?

Back 272

The router has entered router configuration mode but the RIP process has not started.

Front 273

What is the command to set the default gateway on a Cisco switch?

Back 273

'Switch(config)# ip default-gateway ##address## '

Front 274

While working in setup mode, a configuration line is typed incorrectly? What can be done to exit setup mode, without executing or saving any of the mistakes you made?

Back 274

Ctrl-C will exit setup mode without executing or saving any mistakes.

Front 275

What does the command

'transport input ssh' do?

Back 275

It configures a network device to use the SSH protocol on incoming communications.

Front 276

With the use of different ports, some type of NAT maps multiple private IP addresses to a single registered IP address. Which form is it?

Back 276

overloading

Front 277

What is the command used on 2500 routers in the password recovery procedure to bypass the configuration in NVRAM, and boot from Flash?

Back 277

o/r0x2142

Front 278

If a host is forwarding a packet to a host on a different network for the first time, which destination MAC Address will be used in the ARP request.

Back 278

ff-ff-ff-ff-ff-ff

Front 279

What is the default encapsultion for serial interfaces on Cisco routers?

Back 279

HDLC is the default configuration for serial devices on Cisco routers.

Front 280

What technology would you use when a router connected to a LAN has only one WAN interface, but multiple virtual circuits are needed?

Back 280

Frame Relay

Front 281

What does RIP-2 use to prevent loops?

Back 281

Split Horizon and Hold-down Timers

Front 282

A router and a switch are connected, and a technician is working on a computer that is connected to the management console of the switch.

In order to configure the default gateway for the switch, the technicain needs to learn the IP address of the attached router interface.

Which IOS command will provide this information in the absence of Layer 3 connectivity?

Back 282

'show cdp neighbors detail'

Front 283

The protocol that provides the information displayed by the 'show cdp neighbors' command operates at which layer of the OSI model?

Back 283

Data Link

Front 284

What is the command to disable CDP on a single interface?

Back 284

'no cdp enable'

From the interface configuration

Front 285

What is the command to disable CDP on a device?

Back 285

'no cdp run'

From the global configuration

Front 286

What does "inside host" refer to with NAT?

Back 286

Inside host refers to a host in the enterprise network.

Front 287

What does "inside local" refer to with NAT?

Back 287

Inside Local refers to an IP address in an IP header with that address representing a local host as the packet passes over the local enterprise network.

Front 288

What does "inside global" refer to with NAT?

Back 288

Inside Global refers to an IP address in an IP header, with that address representing a local host as the packet passes over the global internet.

Front 289

What does "inside interface" refer to with NAT?

Back 289

Inside Interface is the rotuer interface connected to the same LAN as the inside hosts.

Front 290

What does "outside interface" refer to with NAT?

Back 290

Outside Interface is the router interface connected to the internet.

Front 291

What is PAT?

Back 291

Port Address Translation.

PAT allows the local hosts to use private IP addresses while the access router uses a single public IP address. PAT take advantage fo the facet that server really does not care if it has one connection each to three different hosts or three connections to a single host IP address.

PAT translates the local hosts' private IP addresses to the one registered public IP address. The router keeps track of both the IP address and TCP or UDP port number.

Front 292

What must be modified on a router do perform password recovery?

Back 292

Configuration Register

and

NVRAM

Front 293

When migrating from RIP-1 to RIP-2, what are the differences?

Back 293

RIP-2 supports Authentication

RIP-2 is a classless protocol

RIP-2 also has the same maximum hop count

Front 294

Which two fields in the interface output are useful for detecting Broadcast Storms?

Back 294

'no buffer'

'ignored'

Front 295

PPP is recommended for serial links between routers from different vendors?

(true or false)

Back 295

True.

Cisco HDLC has a proprietary 'type' field.

Front 296

Why is there a problem with serial links using HDLC with routers from different vendors?

Back 296

Cisco HDLC has a proprietary 'Type' field.

Front 297

In the 'show ip interface s0/0' command output, "Serial0/0 is up, line protocol is up" is displayed.

What does "line protocol is up" mean?

Back 297

"line protocol is up" means that keepalives are being received on the interface.

Front 298

What are three types of Flow Control?

Back 298

- Windowing
- Buffering
- Congestion Avoidance

Front 299

The 'setup' command from the privileged mode prompt will cause the device to enter setup mode?

(true or false)

Back 299

True

Front 300

If the DHCP settings have been changed on a DHCP server, and a host is no longer able to connect to a network, what should be done to correct the situation?

Back 300

On the host, use the command 'ip config /release' and then 'renew' in the command prompt.

Front 301

What command would you issue to end a VTY line session?

Back 301

'exit'

Front 302

What effect does it have on network performance when a switch stores an entire frame before forwarding it?

Back 302

Filters all frame errors

Front 303

Which signalling standard is in charge of maintaining the connection and maintaining status between the router and the local frame relay switch?

Back 303

LMI

Front 304

Which form of NAT uses different ports to map multiple private IP addresses to a single registered IP address?

Back 304

Overloading

Front 305

Flow control provides a means for a receiver to govern the amount of data sent by the sender.

(true or false)

Back 305

True.

Front 306

What is PAP?

Back 306

PAP is the Password Authentication Protocol, and is used to authenticate WAN Serial links using PPP.

Front 307

What type of port would you connect a cable with a DB-60 connector to?

Back 307

Serial

Front 308

What command would you issue to find out the type of cable attached to a S0/0 port on a router?

Back 308

'show controllers s0/0'

Front 309

A frame relay subinterface resolves NBMA split horizon issues.

(true or false)

Back 309

True.

Front 310

A frame relay subinterface maps one IP subnet per DLCI.

(true or false)

Back 310

True.

Front 311

In the show IP route output:

R 10.1.2.0 [120/1] via 10.1.128.252, 00:00:09, Serial0/0/1

What does "00:00:09" mean?

Back 311

"00:00:09" is when the route was last seen with a RIP update.

Front 312

A connection between a wireless access point (Ethernet Point) and a switch would need a crossover cable.

(True or false)

Back 312

False. It would use a straight-through.

Front 313

Switch VLAN Interfaces default to a 'shutdown' state.

(True or False)

Back 313

True. VLAN Interfaces are set to 'shutdown' by default, so require a 'no shutdown' command.

Front 314

What is the name of the Frame Relay field used to identify Frame Relay Virtual Circuits?

Back 314

Data-link connection identifiers

Front 315

Where is a DSLAM used, and for what purpose?

Back 315

A DSLAM is used inside a Telco's CO to separate voice traffic from data traffic

Front 316

What is the IEEE standard for the Media Access Control (MAC) sub-layer of Ethernet?

Back 316

802.3

Front 317

What is the IEEE standard for the Logical Link Control (LLC) sub-layer of Ethernet?

Back 317

802.2

Front 318

What is DLCI?

Back 318

Data link connection identifier

It is used in Frame relay, and the WAN switch forwards the frame based on the DLCI, sending the frame the providers network until it gets to the remote-site router on the other side of the Frame Relay cloud.

Front 319

What is 'store and forward' processing mean?

Back 319

The switch waits to receive the entire frame before transmitting. Greatly reduces errors.

Front 320

What is 'cut-through processing?

Back 320

The switch sends the frame as it receives it, which reduces delay.

Front 321

What is 'fragment-free' processing mean in switching?

Back 321

The switch waits until it receives at least 64 bytes of data before transmitting. 64 bytes is the minimum it takes to ensure no collision occurred.