Enterprise BGP Core Network Design - BGP Design and Implementation

Information Technology Reference

In-Depth Information

Figure 5-6

Second Set of Prefix Advertisements for 10.2.0.0/16

EIGRP 102

BGP 65102

R4

R6

10.2.0.0/16

R8

EIGRP 101

BGP 65101

EIGRP 103

BGP 65103

R3

R9

R11

EIGRP 104

BGP 65104

Separately, R8 receives the prefix in AS 65103 via the eBGP session with R6 in AS 65102.

The prefix is installed in R8's routing table and then is advertised via iBGP to R9. The path

received by R9 from R8 is installed in its routing table and is advertised to R11 in AS 65104

and to R3 in AS 65101. This is also shown in Figure 5-6.

R11 receives the prefix in AS 65104 from both R3 in AS 65101 and R9 in AS 65103. The

path received from R3 is installed in the routing table on R11 because of lowest router ID.

R11 advertises the prefix in AS 65104 to R9 in AS 65103 via eBGP. Figure 5-7 shows the

complete flow of advertisement for prefix 10.2.0.0/16.

Figure 5-7

Complete Prefix Advertisement Scenario for 10.2.0.0/16