Consider a network with five nodes, N1 to N5, as
shown as below.
Consider a network with 6 routers R1 to R6 connected
with links having weights as shown in the following
diagram.
The network uses a Distance Vector Routing protocol.
Once the routes have been stabilized, the distance
vectors at different nodes are as follows.
N1 : (0, 1, 7, 8, 4)
N2 : (1, 0, 6, 7, 3)
N3 : (7, 6, 0, 2, 6)
N4 : (8, 7, 2, 0, 4)
N5 : (4, 3, 6, 4, 0)
Each distance vector is the distance of the best known
path at that instance to nodes, N1 to N5, where the
distance to itself is 0. Also, all links are symmetric
and the cost is identical in both directions. In each
round, all nodes exchange their distance vectors with
their respective neighbors. Then all nodes update
their distance vectors. In between two rounds, any
change in cost of a link will cause the two incident
nodes to change only that entry in their distance
vectors.
Explanation : In the next round, every node will send and
receive distance vectors to and from neighbors,
and update its distance vector.
N3 will receive (1, 0, 2, 7, 3) from N2 and it will
update distances to N1 and N5 as 3 and 5
respectively.