IP Routing - IP Routing (2)

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]
R    192.168.215.0 [120/2] via 192.168.20.2, 00:00:23, Serial0/0
R    192.168.115.0 [120/1] via 192.168.20.2, 00:00:23, Serial0/0
R    192.168.30.0 [120/1] via 192.168.20.2, 00:00:23, Serial0/0
C    192.168.20.0 is directly connected, Serial0/0
C    192.168.214.0 is directly connected, FastEthernet0/0

A.	The packet will be discarded.
B.	The packet will be routed out the S0/0 interface.
C.	The router will broadcast looking for the destination.
D.	The packet will be routed out the Fa0/0 interface.

Answer: Option A

Explanation:

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.

10.

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?

A.	The route is 16 hops away.
B.	The route has a delay of 16 microseconds.
C.	The route is inaccessible.
D.	The route is queued at 16 messages a second.

Answer: Option C

Explanation:

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.

11.

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?

A.	The updated information will be added to the existing routing table.
B.	The update will be ignored and no further action will occur.
C.	The updated information will replace the existing routing table entry.
D.	The existing routing table entry will be deleted from the routing table and all routers will exchange routing updates to reach convergence.

Answer: Option B

Explanation:

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.

12.

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

A.	Router(config-if)# no routing
B.	Router(config-if)# passive-interface
C.	Router(config-router)# passive-interface s0
D.	Router(config-router)# no routing updates

Answer: Option C

Explanation:

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

13.

What is split horizon?

A.	Information about a route should not be sent back in the direction from which the original update came.
B.	It splits the traffic when you have a large bus (horizon) physical network.
C.	It holds the regular updates from broadcasting to a downed link.
D.	It prevents regular update messages from reinstating a route that has gone down.

Answer: Option A

Explanation:

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

14.

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
     172.16.0.0/24 is subnetted, 1 subnets
C    172.16.30.0 is directly connected, Loopback0
R    192.168.20.0/24 [120/1] via 192.168.40.1, 00:00:12, Serial0
R    10.0.0.0/8 [120/15] via 192.168.40.1, 00:00:07, Serial0
C    192.168.50.0/24 is directly connected, Ethernet0

A.	172.16.30.0
B.	192.168.30.0
C.	10.0.0.0
D.	All of them will be placed in the neighbor routing table.

Answer: Option C

Explanation:

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.

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 same autonomous system.
RIPv2 supports classless routing.

A.	1, 3 and 5
B.	3 and 4
C.	2 and 5
D.	None of the above

Answer: Option C

Explanation:

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.

16.

Which command displays RIP routing updates?

A.	show ip route
B.	debug ip rip
C.	show protocols
D.	debug ip route

Answer: Option B

Explanation:

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.

IP Routing - IP Routing (2)

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