It is important to understand what happens when a distance-vector pro-
tocol starts up. In Figure 2.4, the four routers start off with only their directly connected networks in the routing table. After a distance-vector protocol is started on each router, the routing tables are updated with all route infor- mation gathered from neighbor routers.
F I G U R E 2 . 4
The internetwork with distance-vector routing
As shown in Figure 2.4, each router has only the directly connected net-
works in each routing table. Each router sends its complete routing table out to each active interface on the router. The routing table of each router includes the network number, exit interface, and hop count to the network.