Border Gateway Protocol - CCIE Routing and Switching Exam Certification Guide - page 452

BGP Confederations Figure 9-10

Full iBGP mesh with no confederation

to AS 1 to AS 2

AS 100

B

A

G

F

C

to AS 6

to AS 3

D E

to AS 4 to AS 5

iBGP connections reduced with confederation

to AS 1 to AS 2

Confederation 100

Router A
Loopback: 1.1.1.1

Router B
Loopback: 1.1.1.2

Router G
Loopback: 1.1.1.7

Router C
Loopback: 1.1.1.3

Router F
Loopback: 1.1.1.6

Router D
Loopback: 1.1.1.4

Router E
Loopback: 1.1.1.5

to AS 6

to AS 3

AS 10 AS 20

to AS 4 to AS 5

The configuration for all routers from Figure 9-10 is shown in Example 9-16. Routers A, B, and
G are configured for eBGP between the private autonomous systems. These routers are
configured with the bgp confederation identifier command. The confederation identifier
number is the same for all routers in the network. The bgp confederation command identifies
the AS number of other private autonomous systems in the confederation. Because Router A