Configure IPv6 BGP Community Properties

Network Requirements

• Set up EBGP neighbors between Device1 and Device2.
• Device1 introduces two direct-connect routes 2001:1::/64 and 2001:2::/64 to BGP in network mode, and set different community properties for two routes that are advertised to Device2.
• When Device2 receives routes from Device1, it applies community properties in the incoming direction of a neighbor to filter route 2001:1::/64 and allow route 2001:2::/64.

Network Topology

Figure 13–3 Networking for configuring IPv6 BGP community properties

Configuration Steps

Step 1: Configure the IPv6 global unicast addresses of the interfaces. (Omitted)

Step 2: Configure the IPv6 BGP basic functions.

#Configure Device1.

#Configure Device2.

#On Device1, check the IPv6 BGP neighbor status.

Device1#show bgp ipv6 unicast summary  
BGP router identifier 1.1.1.1, local AS number 100 BGP table version is 1 
1 BGP AS-PATH entries 0 BGP community entries 
 
Neighbor     V  AS    MsgRcvd MsgSent TblVer InQ OutQ Up/Down    State/PfxRcd
2001:3::2   4  200   3            4           1        0     0       00:01:02   0 
 
Total number of neighbors 1 

IPv6 BGP neighbors have been successfully set up between Device1 and Device2.

#Query the route table of Device2.

Device2#show ipv6 route  
Codes: C - Connected, L - Local, S - static, R - RIP, B - BGP, i-ISIS 
       U - Per-user Static route 
       O - OSPF, OE-OSPF External, M - Management 
 
L ::1/128 [0/0] 
     via ::, 1w2d:05:45:34, lo0
B 2001:1::/64 [20/0] 
     via 2001:3::1, 00:01:35, vlan2
B 2001:2::/64 [20/0] 
     via 2001:3::1, 00:01:35, vlan2
C 2001:3::/64 [0/0] 
     via ::, 00:04:09, vlan2
L 2001:3::2/128 [0/0] 
     via ::, 00:04:08, lo0 

According to the queried information, Device2 has successfully learnt routes 2001:1::/64 and 2001:2::/64.

Step 3: Configure the ACL and routing policy, and set IPv6 BGP community properties.

#Configure Device1.

Set different community properties for routes 2001:1::/64 and 2001:2::/64 respectively by configuring an ACL and routing policy.

Step 4: Configure a routing policy for IPv6 BGP.

#Configure Device1.

#View the IPv6 BGP route table of Device2.

Device2#show bgp ipv6 unicast 2001:1::/64
BGP routing table entry for 2001:1::/64 
Paths: (1 available, best #1, table Default-IP-Routing-Table) 
  Not advertised to any peer 
  100 
    2001:3::1 (metric 10) from 2001:3::1 (1.1.1.1) 
     Origin IGP, metric 0, localpref 100, valid, external, best 
      Community: 100:1 
      Last update: 00:00:24 ago

Device2#show bgp ipv6 unicast 2001:2::/64
BGP routing table entry for 2001:2::/64 
Paths: (1 available, best #1, table Default-IP-Routing-Table) 
  Not advertised to any peer 
  100 
    2001:3::1 (metric 10) from 2001:3::1 (1.1.1.1) 
     Origin IGP, metric 0, localpref 100, valid, external, best 
      Community: 100:2 
      Last update: 00:00:30 ago

According to the IPv6 BGP route table of Device2, the community property of route 2001:1::/64 is set to 100:1, and the community properties of route 2001:2::/64 is set to 100:2.

Step 5: Configure IPv6 BGP route filtration.

#Configure Device2.

Step 6: Check the result.

#View the route table of Device2.

Device2#show ipv6 route 
Codes: C - Connected, L - Local, S - static, R - RIP, B - BGP, i-ISIS 
       U - Per-user Static route 
       O - OSPF, OE-OSPF External, M - Management 
 
L ::1/128 [0/0] 
     via ::, 1w2d:05:58:57, lo0
B 2001:2::/64 [20/0] 
     via 2001:3::1, 00:00:05, vlan2
C 2001:3::/64 [0/0] 
     via ::, 00:17:32, vlan2
L 2001:3::2/128 [0/0] 
     via ::, 00:17:30, lo0

According to the IPv6 BGP route table of Device2, route 2001:1::/64 has been filtered in the incoming direction, and route 2001:2::/64 has been allowed.

• ---

  After a routing policy is configured on the IPv6 BGP neighbor, the IPv6 BGP must be reset to make the configuration take effect.
• You must configure the send-community command to advertise the community property to the peer.

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