Count to infinity problem in DV Routing

The main issue with Distance Vector Routing (DVR) protocols is Routing

Loops, since Bellman-Ford Algorithm cannot prevent loops.

 This routing loop in DVR network causes Count to Infinity Problem.

 Routing loops usually occur when any interface goes down or two-

routers send updates at the same time.

Counting to infinity problem:

 Bellman-Ford algorithm will converge for each router, they will have

entries for each other.

 B will know that it can get to C at a cost of 1, and A will know that it

can get to C via B at a cost of 2.

 If the link between B and C is disconnected, then B will know that it

can no longer get to C via that link and will remove it from it’s table.

 Before it can send any updates it’s possible that it will receive an

update from A which will be advertising that it can get to C at a cost

of 2.

Link Cost = Number of hops (RIP)

iterations

2 --> C

2+1 -->C

3+1=4 --> C

20 Count to infinity problem in DV Routing Route Poisoning Split Horizon

Computer Networks (BC2001)