29.3.3 Confirming BGP4 + route selection

To check the BGP4+ route selection result, use the show ipv6 bgp operation command.

Figure 29-12: Result of executing show ipv6 bgp command
# show ipv6 bgp Date 20XX/10/18 22:44:23 UTC Local AS: 65531, Local Router ID: 192.168.1.100 Status Codes: d dampened, * valid, > active, S Stale, r RIB failure Origin Codes: i - IGP, e - EGP, ? - incomplete Network Next Hop MED LocalPref weight Path > 3ffe:10:10::/64 fe80::200:87ff:fe16:90d5%VLAN0005 - 120 20 65532 65528 i ..1 3ffe:10:10::/64 3ffe:10:2:2::2 - 80 20 65533 65533 65529 i ..2 * 3ffe:10:10::/64 3ffe:10:1:2::2 - 80 10 65534 i ..3 > 3ffe:10:20::/64 fe80::200:87ff:fe16:90d5%VLAN0005 - 80 20 65532 65528 i ..4 3ffe:10:20::/64 3ffe:10:2:2::2 - 80 20 65533 65533 65529 i ..5 > 3ffe:172:20::/64 3ffe:10:1:2::2 - 100 10 65534 i ..6 3ffe:172:20::/64 3ffe:192:168:2::2 - 100 10 65530 ? ..7 > 3ffe:172:30::/64 3ffe:10:1:2::2 - 100 10 65534 i ..8 3ffe:172:30::/64 3ffe:192:168:2::2 100 100 10 65530 i ..9 > 3ffe:192:168:10::/64 3ffe:10:1:2::2 - 100 10 65534 i ..10 3ffe:192:168:10::/64 3ffe:192:168:2::2 - 100 10 65530 i ..11 > 3ffe:192:169:10::/64 3ffe:192:168:2::2 - 100 10 65530 i ..12 > 3ffe:192:169:20::/64 3ffe:192:168:2::2 - 100 10 65530 i ..13

Figure 29-12: Result of executing show ipv6 bgp command

# show ipv6 bgp
Date 20XX/10/18 22:44:23 UTC
Local AS: 65531, Local Router ID: 192.168.1.100
Status Codes: d dampened, * valid, > active, S Stale, r RIB failure
Origin Codes: i - IGP, e - EGP, ? - incomplete
   Network                                     Next Hop
         MED    LocalPref weight Path
*> 3ffe:10:10::/64                            fe80::200:87ff:fe16:90d5%VLAN0005
         -      120        20     65532 65528 i                             ..1
*  3ffe:10:10::/64                            3ffe:10:2:2::2
         -      80         20     65533 65533 65529 i                       ..2
*  3ffe:10:10::/64                            3ffe:10:1:2::2
         -      80         10     65534 i                                   ..3
*> 3ffe:10:20::/64                            fe80::200:87ff:fe16:90d5%VLAN0005
         -      80         20     65532 65528 i                             ..4
*  3ffe:10:20::/64                            3ffe:10:2:2::2
         -      80         20     65533 65533 65529 i                       ..5
*> 3ffe:172:20::/64                           3ffe:10:1:2::2
         -      100        10     65534 i                                   ..6
*  3ffe:172:20::/64                           3ffe:192:168:2::2
         -      100        10     65530 ?                                   ..7
*> 3ffe:172:30::/64                           3ffe:10:1:2::2
         -      100        10     65534 i                                   ..8
*  3ffe:172:30::/64                           3ffe:192:168:2::2
         100    100        10     65530 i                                   ..9
*> 3ffe:192:168:10::/64                       3ffe:10:1:2::2
         -      100        10     65534 i                                  ..10
*  3ffe:192:168:10::/64                       3ffe:192:168:2::2
         -      100        10     65530 i                                  ..11
*> 3ffe:192:169:10::/64                       3ffe:192:168:2::2
         -      100        10     65530 i                                  ..12
*> 3ffe:192:169:20::/64                       3ffe:192:168:2::2
         -      100        10     65530 i                                  ..13

1 to 3. 3ffe:10:10::/64 route selection: Routes 1 and 2 are preferred by comparing the weights of the three routes, and then 1 is selected by comparing the LOCAL_PREF values of 1 and 2.
4 to 5. 3ffe:10:20::/64 route selection: Route 4 is selected by comparing the AS_PATH length of each route.
6 to 7. 3ffe:172:20::/64 route selection: Route 6 is selected by comparing the ORIGIN attribute of each route.
8 to 9. 3ffe:172:30::/64 route selection: Route 8 is selected by comparing the MED attribute of each route.
10~11. 3ffe:192:168:10::/64 route selection: Route 10 is selected by comparing the peer BGP identifier of each route.
12~13. 3ffe:192:169:10::/64, 3ffe:192:169:20::/64 route selection: Route 12 and route 13 are selected because there are no other routes to the destinations.