Configuring a BGP Confederation
Context
A confederation divides an AS into sub-ASs. Within each sub-AS, IBGP peers establish full-mesh connections or have an RR configured. Sub-ASs establish EBGP connections. On a large BGP network, configuring a confederation can reduce the number of IBGP connections, simplify routing policy management, and improve route advertisement efficiency.
Procedure
- Run system-view
The system view is displayed.
- Run bgp { as-number-plain | as-number-dot }
BGP is enabled and the BGP view is displayed.
- Run confederation id { as-number-plain | as-number-dot }
A confederation ID is configured.
By default, no BGP confederation is configured.
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An old speaker that has a 2-byte AS number cannot be in the same confederation with a new speaker that has a 4-byte AS number. Otherwise, a routing loop may occur. This is because the AS4_Path attribute does not support confederations.
- Run confederation peer-as { as-number-plain | as-number-dot } &<1-32>
A sub-AS number is configured for a confederation.
By default, no sub-AS number of the confederation is configured.
- (Optional) Run confederation nonstandard
Confederation compatibility is configured.
By default, confederations comply with RFC 3065.
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