Large-Scale IP Network Solutions (CCIE Professional Development)

Review Questions

1:	How and why is IBGP used for interdomain routing?
2:	Is it possible to have two BGP sessions between routers for redundancy?
3:	How many BGP sessions, routes, and updates/per second can a router handle?

Answers:

1:

How and why is IBGP used for interdomain routing?

A1:

Some early deployments of BGP redistributed routes learned via EBGP into the IGP (OSPF/IS-IS), and carried the routes via both the IBGP and IGP. A border router would not readvertise routes learned via IBGP until the same routes were visible in the IGP—that is, until IBGP and the IGP were synchronized. However, commonly used IGPs do not scale particularly well to tens of thousands of routes, so this approach is now rarely used. Instead, the IGP carries just ...