Question 1

If your routing table has a static, a RIP, and an IGRP route to the same network, which route will be used to route packets by default?

Accepted Answer

Static routes have an administrative distance of 1 by default. Unless you change this, a static route will always be used over any other found route. IGRP has an administrative distance of 100, and RIP has an administrative distance of 120, by default.

Question 2

What command is used to stop RIP routing updates from exiting out an interface but still allow the interface to receive RIP route updates?

Accepted Answer

The (config-router)#passive-interface command stops updates from being sent out an interface, but route updates are still received.

Question 3

What is route poisoning?

Accepted Answer

Another way to avoid problems caused by inconsistent updates and to stop network loops is route poisoning. When a network goes down, the distance-vector routing protocol initiates route poisoning by advertising the network with a metric of 16, or unreachable (sometimes referred to as infinite).

Question 4

Network 206.143.5.0 was assigned to the Acme Company to connect to its ISP. The administrator of Acme would like to configure one router with the commands to access the Internet. Which commands could be configured on the Gateway router to allow Inte…

Accepted Answer

There are actually three different ways to configure the same default route, but only two are shown in the answer. First, you can set a default route with the 0.0.0.0 0.0.0.0 mask and then specify the next hop, as in option A. Or you can use 0.0.0.0 0.0.0.0 and use the exit interface instead of the next hop. Finally, you can use option D with the ip default-network command.

Question 5

Which of the following is true regarding RIPv2?

Accepted Answer

RIPv2 is pretty much just like RIPv1. It has the same administrative distance and timers and is configured just like RIPv1.

Question 6

What is split horizon?

Accepted Answer

A split horizon will not advertise a route back to the same router it learned the route from.

Question 7

You have the following routing table. Which of the following networks will not be placed in the neighbor routing table? R    192.168.30.0/24 [120/1] via 192.168.40.1, 00:00:12, Serial0
C    192.168.40.0/24 is directly connected, Serial0
     172.1…

Accepted Answer

The network 10.0.0.0 cannot be placed in the next router's routing table because it already is at 15 hops. One more hop would make the route 16 hops, and that is not valid in RIP networking.

Question 8

A network administrator views the output from the show ip route command. A network that is advertised by both RIP and IGRP appears in the routing table flagged as an IGRP route. Why is the RIP route to this network not used in the routing table?

Accepted Answer

RIP has an administrative distance (AD) of 120, while IGRP has an administrative distance of 100, so the router will discard any route with a higher AD than 100.

Question 9

Two connected routers are configured with RIP routing. What will be the result when a router receives a routing update that contains a higher-cost path to a network already in its routing table?

Accepted Answer

When a routing update is received by a router, the router first checks the administrative distance (AD) and always chooses the route with the lowest AD. However, if two routes are received and they both have the same AD, then the router will choose the one route with the lowest metrics, or in RIP's case, hop count.

Question 10

Which two of the following are true regarding the distance-vector and link-state routing protocols? Link state sends its complete routing table out all active interfaces on periodic time intervals. Distance vector sends its complete routing table ou…

Accepted Answer

The distance-vector routing protocol sends its complete routing table out all active interfaces at periodic time intervals. Link-state routing protocols send updates containing the state of its own links to all routers in the internetwork.

Question 11

You type debug ip rip on your router console and see that 172.16.10.0 is being advertised to you with a metric of 16. What does this mean?

Accepted Answer

You cannot have 16 hops on a RIP network by default. If you receive a route advertised with a metric of 16, this means it is inaccessible.

Question 12

What does RIPv2 use to prevent routing loops? CIDR Split horizon Authentication Classless masking Holddown timers

Accepted Answer

RIPv2 uses the same timers and loop-avoidance schemes as RIPv1. Split horizon is used to stop an update from being sent out the same interface it was received on. Holddown timers allow time for a network to become stable in the case of a flapping link.

Question 13

IGRP uses which of the following as default parameters for finding the best path to a remote network? Hop count MTU Cumulative interface delay STP Path bandwidth value

Accepted Answer

IGRP uses bandwidth and delay of the line, by default, to determine the best path to a remote network. Delay of the line can sometimes be called the cumulative interface delay.

Question 14

Which command displays RIP routing updates?

Accepted Answer

The debug ip rip command is used to show the Internet Protocol (IP) Routing Information Protocol (RIP) updates being sent and received on the router.

Question 15

Which statement is true regarding classless routing protocols? The use of discontiguous networks is not allowed. The use of variable length subnet masks is permitted. RIPv1 is a classless routing protocol. IGRP supports classless routing within the …

Accepted Answer

Classful routing means that all hosts in the internetwork use the same mask. Classless routing means that you can use Variable Length Subnet Masks (VLSMs) and can also support discontiguous networking.

Question 16

The Corporate router receives an IP packet with a source IP address of 192.168.214.20 and a destination address of 192.168.22.3. Looking at the output from the Corporate router, what will the router do with this packet? Corp#sh ip route
[output cut…

Accepted Answer

Since the routing table shows no route to the 192.168.22.0 network, the router will discard the packet and send an ICMP destination unreachable message out interface FastEthernet 0/0, which is the source LAN where the packet originated from.

Question 17

Which of the following statements are true regarding the command ip route 172.16.4.0 255.255.255.0 192.168.4.2? The command is used to establish a static route. The default administrative distance is used. The command is used to configure the defaul…

Accepted Answer

Although answer D almost seems right, it is not; the mask is the mask used on the remote network, not the source network. Since there is no number at the end of the static route, it is using the default administrative distance of 1.

IP Routing Questions