Consider a campusarea network that runs the distancevector r

Consider a campus-area network that runs the distance-vector routing protocol RIP (Routing Information Protocol), where router K has the following routing table. Suppose router K receives the following routing update from router J. Give router K\'s routing table after it incorporates this update from router J. Note that RIP assumes that the distance over each network (i.e., between two neighbor routers) is 1.

Solution

In distance vector routing each node shares its routing table with its immediate neighbours periodically and when there is a change.

1. Initial routing table of K

2. Modifies its routing table based on values received from Router J, assuming distance between Router K and J is 1 hop. It adds the cost between K and J(i.e. 1 hop) with each value in the second column of the table provided by J, since to reach a destination it needs to go through J.

3. Router K now comapres the new updated table with the initial table of its own and selects the shortest distance routes. If it learns of a new network it adds the entry to its table like for Net 22. If the next node entry is same, K chooses the new row entry. So for destination Net 42, the previous value through J was 2, but now it is 4. Since J is the node from which the value has been received, the new entry is chosen.

K\'s Routing table initially

Destination	Distance	Next Hop
Net 1	0	direct
Net 2	0	direct
Net 5	8	Router L
Net 17	6	Router M
Net 24	6	Router J
Net 30	2	Router Q
Net 42	2	Router J