Company B ran RIP as its interior routing protocol, as shown in Figure 10.2,
because Company B's network had mixture of routing vendors. One day, Company A and Company B merged.
F I G U R E 1 0 . 2
Company B's RIP configuration
When the backbone routers of each company were interconnected, as
illustrated in Figure 10.3, the Company A routers did not automatically learn the routes from the Company B routers, nor vice versa. A common mis- conception is that if the router joining two networks runs both routing pro- tocols, then route redistribution will just happen--this is not so.