Refer to the exhibit.
The network shown in the exhibit is running the RIPv2 routing protocol. The network has converged, and the routers in this network are functionning properly.
The FastEthernet0/0 interface on R1 goes down. in which two ways will the routers in this network respond to this change? (choose two)
A.
R1 will send LSAs to R2 and R3 informing them of this change, and then all routers will send periodic updates at an increased rate until the network again converges.
B.
Because of the split-horizon rule, router R2 will be prevented from sending erroneous information to R1 about connectivity to the 192.168.1.0 network.
C.
When router R2 learns from R1 that the link to the 192.168.1.0 network has been lost, R2 will respond by sending a route back to R1 with an infinite metric to the
network.
D.
Routers R2 and R3 mark the route as inaccessible and will not accept any further routing updates from R1 until their hold-down timers expire.
E.
All routers will reference their topology database to determine if any backup routes to the 192.168.1.0 network are known.
Explanation:
RIP version 2 will send triggered updates when the topology changes like when a link goes down.
The following are the key characteristics of RIPv2 pertaining to this question:1. Split horizon – RIP doesn’t advertise routes back out the interface in which they came. Or put another way, a router won’t tell a neighbor about routes that the neighbor presumably already knows about. That would be silly, and could cause a loop in certain circumstances.
2. Triggered update – RIP will send an update out just a soon as the routing table changes. He won’t wait for the Update timer to expire.
3. Route poisoning- RIP will tell other routers that a failed route is junk by advertising it with an infinite metric (which is 16 for RIP), effectively poisoning it.
Reference: http://www.ethanbanks.net/7rrp200702