ECS4660-28F_Management Guide-R03

C HAPTER 51 | IP Routing Commands
Border Gateway Protocol (BGPv4)
– 1843 –
dividing up a large AS into several smaller ASes, where only the peers
in the same smaller AS are fully meshed, thus reducing the number of
required connections and routing traffic.
◆ Even though different local confederation peers may have external BGP
(eBGP) sessions, they exchange routing information among themselves
as if they were iBGP peers. Next hop, Multi Exit Discriminator (MED),
and local preference information is preserved. By preserving this
information, a single Interior Gateway Protocol (IGP) can be used
among the local confederations. When viewed from the outside by
external peers, the larger AS is still identified as a single entity or
autonomous system.
◆ Use the bgp confederation peer command to specify the autonomous
systems within a confederation.
EXAMPLE
Console(config-router)#bgp confederation identifier 600
Console(config-router)#
RELATED COMMANDS
bgp confederation peer (1843)
bgp confederation
peer
This command adds an internal peer autonomous system to a
confederation. Use the no form to remove an autonomous system from a
confederation.
SYNTAX
bgp confederation peer as-number
no bgp confederation identifier
as-number – Autonomous system number which identifies this
router as a member of the specified domain, and tags routing
messages passed to other BGP routers with this number.
(Range: 1-4294967295)
COMMAND MODE
Router Configuration
DEFAULT SETTING
No confederation peer is configured.
COMMAND USAGE
◆ This command is used to add multiple ASes to a confederation. Each AS
is fully meshed within itself, and the AS members are visible internally
within the confederation.
◆ Use the bgp confederation identifier command to create a
confederation.