Configuring a BGP4+ Confederation
On a large BGP4+ network, configuring a BGP4+ confederation reduces the number of IBGP connections and simplifies routing policy management, which increases the route advertisement efficiency.
Usage Scenario
A confederation is a solution to the increasing number of IBGP connections in an AS. The confederation divides an AS into multiple sub-ASs. In each sub-AS, IBGP peer relationships are set up or an RR is configured on one of the IBGP peers. EBGP connections are set up between sub-ASs.
Pre-configuration Tasks
Before configuring a BGP4+ confederation, complete the following tasks:
Configure link layer protocol parameters and assigning IP addresses to the interfaces to ensure that the status of the link layer protocol of the interface is Up.
Procedure
- Configure a BGP4+ confederation.
Perform the following steps on the BGP4+ router:
- Run confederation peer-as as-number &<1-32>
The number of the sub-AS of other EBGP peers is set.
The parameter as-number used is valid only in the confederation.
The confederation id and confederation peer-as commands must be run for all the EBGP peers in a confederation, and the EBGP peers must have the same confederation ID.
The old speaker supporting 2-byte AS numbers and the new speaker supporting 4-byte AS numbers cannot exist in the same confederation. Otherwise, routing loops may occur because AS4_Path does not support confederations.
- Run confederation peer-as as-number &<1-32>
- Configure the compatibility of the confederation.
If some routers in a confederation do not comply with the standard protocols, you can perform the following steps so that the local device is compatible with them:
Checking the Configuration
- Run the display bgp ipv6 peer [ ipv6-address ] verbose command to check detailed information about the peer.
- Run the display bgp ipv6 routing-table [ ipv6-address prefix-length ] command to check information about the BGP routing table.