BGP IPv6 - Community String
Community String
The BGP (Border Gateway Protocol) IPv6 Community String is a mechanism designed for tagging and categorizing BGP routes within an Autonomous System (AS) using IPv6. Similar to its IPv4 counterpart, the IPv6 Community String is a 32-bit value that serves as a label attached to BGP route advertisements. Network administrators use community strings to convey specific information about routes, allowing for more granular control over route policies and distribution within the AS. IPv6 Community Strings can be defined and assigned based on the organization's policies, enabling routers to make informed decisions about route advertisement, filtering, and preference. This flexibility makes the IPv6 Community String a powerful tool for managing and controlling routing behavior within BGP IPv6 networks, supporting the implementation of diverse policies for efficient and tailored network operations.
Lab:
Disclaimer
This Configuration Guide is designed to assist members to enhance their skills in particular technology area. While every effort has been made to ensure that all material is as complete and accurate as possible, the enclosed material is presented on an “as is” basis. Neither the authors nor Forum assume any liability or responsibility to any person or entity with respect to loss or damages incurred from the information contained in this guide. This configuration guide was developed by Forum. Any similarities between material presented in this configuration guide and any other material is completely coincidental.
Cisco IOS Software, Linux Software (I86BI_LINUX-ADVENTERPRISEK9-M), Version 15.2(4)M1, DEVELOPMENT TEST SOFTWARE
Task 1: Configure IPv6 BGP Community String
Step 1: In the configuration mode of router configure Community String Attributes by following command:
R1:
router bgp 65100
address-family ipv6
neighbor 22:0:1::2 send-community
neighbor 22:0:1::2 route-map bbb out
exit
route-map bbb permit 10
set community 8888
exit
Step 2: Verify receipt of route in neighbor router’s by following command
R2#show bgp ipv6 unicast community
BGP table version is 20, local router ID is 22.0.3.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*> 11:0:1::/64 11:0:1::1 0 0 65100 i
*> 11:0:2::/64 11:0:1::1 0 0 65100 i
*> 11:0:3::/64 11:0:1::1 0 0 65100 i
R2#show ip bgp community 8888
BGP table version is 20, local router ID is 22.0.3.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*> 11:0:1::/64 11:0:1::1 0 0 65100 i
*> 11:0:2::/64 11:0:1::1 0 0 65100 i
*> 11:0:3::/64 11:0:1::1 0 0 65100 i
R2#show bgp ipv6 unicast 11:0:1::0/64
BGP routing table entry for 11:0:1::/64, version 18
Paths: (1 available, best #1, table default)
Advertised to update-groups: 2
Refresh Epoch 2
65100, (received & used)
11:0:1::1 (metric 64) from 11:0:1::1 (11.0.3.1)
Origin IGP, metric 0, localpref 100, valid, external, best
Community: 8888
11 network is tagged 8888 community
Task 2: Configure IPv6 BGP Community String Manipulation
Step 1: In the configuration mode of router configure Community String Manipulation by following command:
R2:
router bgp 65000
address-family ipv6
neighbor 11:0:1::1 route-map bbb in
exit
ip community-list 1 permit 8888
route-map bbb permit 10
match community 1
set weight 9999
exit
Step 2: Verify receipt of route in neighbor router’s by following command
R2#show bgp ipv6 unicast community
BGP table version is 24, local router ID is 22.0.3.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*> 11:0:1::/64 11:0:1::1 0 9999 65100 i
*> 11:0:2::/64 11:0:1::1 0 9999 65100 i
*> 11:0:3::/64 11:0:1::1 0 9999 65100 i
R2#show bgp ipv6 unicast
BGP table version is 24, local router ID is 22.0.3.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*> 11:0:1::/64 11:0:1::1 0 9999 65100 i
*> 11:0:2::/64 11:0:1::1 0 9999 65100 i
*> 11:0:3::/64 11:0:1::1 0 9999 65100 i
*> 22:0:1::/64 :: 0 32768 i
*> 22:0:2::/64 :: 0 32768 i
*> 22:0:3::/64 :: 0 32768 i
*>i 33:0:1::/64 33:0:1::3 0 100 0 i
*>i 33:0:2::/64 33:0:1::3 0 100 0 i
*>i 33:0:3::/64 33:0:1::3 0 100 0 i
*>i 44:0:1::/64 44:0:1::4 0 100 0 65200 i
*>i 44:0:2::/64 44:0:1::4 0 100 0 65200 i
*>i 44:0:3::/64 44:0:1::4 0 100 0 65200 i
Policy is called to match only 8888 community and will change weight attribute to 9999 . Hence manipulation is achieved with the help of Community String.