# 1.0. Suppose the network is as follows, where distance-vector routing update is used. Each link has…

1.0. Suppose the network is as follows, where distance-vector

routing update is used. Each link has cost 1, and each router has

entries in its forwarding table only for its immediate neighbors

(so A’s table contains 〈B,B,1〉, 〈D,D,1〉 and B’s table contains

〈A,A,1〉, 〈C,C,1〉).

(a). Suppose each node creates a report from its initial

configuration and sends that to each of its neighbors. What will

each node’s forwarding table be after this set of exchanges? The

exchanges, in other words, are all conducted simultaneously; each

node first sends out its own report and then processes the reports

arriving from its two neighbors.

(b). What will each node’s table be after the

simultaneous-and-parallel exchange process of part (a) is repeated

a second time?

Hint: you do not have to go through each exchange in detail; the

only information added by an exchange is additional

reachability information.