Concept Guide
confederations appear as one AS. Within the confederation sub-AS, the IBGP neighbors are fully meshed and the MED, NEXT_HOP, and
LOCAL_PREF attributes are maintained between confederations.
To congure BGP confederations, use the following commands.
• Species the confederation ID.
CONFIG-ROUTER-BGP mode
bgp confederation identifier as-number
– as-number: from 0 to 65535 (2 Byte) or from 1 to 4294967295 (4 Byte).
• Species which confederation sub-AS are peers.
CONFIG-ROUTER-BGP mode
bgp confederation peers as-number [... as-number]
– as-number: from 0 to 65535 (2 Byte) or from 1 to 4294967295 (4 Byte).
All Confederation routers must be either 4 Byte or 2 Byte. You cannot have a mix of router ASN support.
To view the conguration, use the show config command in CONFIGURATION ROUTER BGP mode.
Conguring a BGP VRF address family
To perform BGP conguration between two neighbors that must exchange IPv6 or IPv4 VRF information, use the following commands.
Following are the steps to congure BGP VRF address-family between two peers.
• Congure a VRF routing table.
CONFIG mode
ip vrf vrf-name
For more information on VRF conguration, see Virtual Routing and Forwarding (VRF).
• Enter the router conguration mode and the AS number.
CONFIG mode
router bgp as-number
• Specify the IPv4 address family conguration.
CONFIG-ROUTER-BGP mode
address-family {ipv4 [multicast] | ipv6 unicast} vrf vrf-name
vrf vrf-name — Species the name of VRF instance associated with the IPv4 or IPv6 address-family conguration.
• Add the IP address of the neighbor in the specied AS to the IPv4 MBGP neighbor table.
CONFIG-ROUTER-BGP-AF mode
neighbor {ip-address | ipv6–address | peer-group-name} remote-as as-number
• Enable the neighbor.
CONFIG-ROUTER-BGP mode
neighbor ip-address no shutdown
• Specify the number of prexes that can be received from a neighbor.
CONFIG-ROUTER-BGP-AF mode
neighbor {ip-address | ipv6–address | peer-group-name} maximum—prefix maximum [threshold]
[warning-only]as-number
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Border Gateway Protocol (BGP)