Enterprise BGP Core Network Design - BGP Design and Implementation - page 169

Table 5-2 summarizes the path-selection process for each router.
Table 5-2 Path-Selection Summarization

ASN Router Path Information and Selection Criteria

65101 R3

(R9) 65103 65102
172.16.13.2 from 172.16.13.2 (172.16.9.1)
Origin IGP, localpref 100, valid, external
(R4) 65102
172.16.13.6 from 172.16.13.6 (172.16.4.1)
Origin IGP, metric 307200, localpref 100, valid, external, best
The path from R4 has the shortest AS_PATH.

65102 R4

(R6) Local
172.16.6.1 (metric 409600) from 172.16.6.1 (172.16.6.1)
Origin IGP, metric 307200, localpref 100, valid, internal
(R4) Local
172.17.2.1 from 0.0.0.0 (172.16.4.1)
Origin IGP, metric 307200, localpref 100, weight 32768, valid,
sourced, local, best
The path is locally sourced, and WEIGHT is set to 32768.

65102 R6

(R4) Local
172.16.4.1 (metric 409600) from 172.16.4.1 (172.16.4.1)
Origin IGP, metric 307200, localpref 100, valid, internal
(R6) Local
172.17.2.1 from 0.0.0.0 (172.16.6.1)
Origin IGP, metric 307200, localpref 100, weight 32768, valid,
sourced, local, best
The path is locally sourced, and WEIGHT is set to 32768.

65103 R8

(R6) 65102
172.16.13.13 from 172.16.13.13 (172.16.6.1)
Origin IGP, metric 307200, localpref 100, valid, external, best
Only one path is received—the de facto winner.

65103 R9

(R11) 65104 65101 65102
172.16.13.18 from 172.16.13.18 (172.16.11.1)
Origin IGP, localpref 100, valid, external
(R8) 65102
172.16.8.1 (metric 409600) from 172.16.8.1 (172.16.8.1)
Origin IGP, metric 307200, localpref 100, valid, internal, best
(R3) 65101 65102
172.16.13.1 from 172.16.13.1 (172.16.3.1)
Origin IGP, localpref 100, valid, external
The path from R8 has the shortest AS_PATH.

65104 R11

(R9) 65103 65102
172.16.13.17 from 172.16.13.17 (172.16.9.1)
Origin IGP, localpref 100, valid, external
(R3) 65101 65102
172.16.13.9 from 172.16.13.9 (172.16.3.1)
Origin IGP, localpref 100, valid, external, best
The path from R3 has the lowest ROUTER_ID.