What is route poisoning?
Answer: D
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).
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What does RIPv2 use to prevent routing loops?
1.CIDR
2.Split horizon
3.Authentication
4.Classless masking
5.Holddown timers
Answer: C
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.
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Which two of the following are true regarding the distance-vector and link-state routing protocols?
1.Link state sends its complete routing table out all active interfaces on periodic time intervals.
2.Distance vector sends its complete routing table out all active interfaces on periodic time intervals.
3.Link state sends updates containing the state of its own links to all routers in the internetwork.
4.Distance vector sends updates containing the state of its own links to all routers in the internetwork.
Answer: C
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.
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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
Answer: C
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.
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Which statement is true regarding classless routing protocols?
1.The use of discontiguous networks is not allowed.
2.The use of variable length subnet masks is permitted.
3.RIPv1 is a classless routing protocol.
4.IGRP supports classless routing within the same autonomous system.
5.RIPv2 supports classless routing.
Answer: C
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.
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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
Answer: A
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.
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Which command displays RIP routing updates?
Answer: B
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.
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IGRP uses which of the following as default parameters for finding the best path to a remote network?
1.Hop count
2.MTU
3.Cumulative interface delay
4.STP
5.Path bandwidth value
Answer: B
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.
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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 Internet access to the entire network?
1.Gateway(config)# ip route 0.0.0.0 0.0.0.0 206.143.5.2
2.Gateway(config)# router rip
3.Gateway(config-router)# network 206.143.5.0
4.Gateway(config-router)# network 206.143.5.0 default
Answer: D
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.
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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?
Answer: B
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.
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