User guide

Configuring BGP BGP Overview
OmniSwitch AOS Release 7 Advanced Routing Configuration Guide March 2015 page 4-11
Since the router clients in this scenario only peer with the router reflector, the session load per router is
significantly reduced. Route Reflectors are discussed further in “Setting Up Route Reflection” on
page 4-41.
BGP Confederations
Confederations are another way of dealing with large networks with many BGP speakers. Like route
reflectors, confederations are recommended when speakers are forced to handle large numbers of BGP
sessions at the same time.
Confederations are sub ASs within a larger AS. Inside each sub AS, all the rules of IBGP apply. Since
each sub AS has its own AS number, EBGP must be used to communicate between sub ASs. The
following example demonstrates a simple confederation set up:
AS 100 is now a confederation consisting of AS 1001 and AS 1002. Even though EBGP is used to
communicate between AS 1001 and 1002, the entire confederation behaves as though it were using IBGP.
In other words, the sub AS attributes are preserved when crossing the sub AS boundaries.
Confederations are discussed further in “Creating a Confederation” on page 4-46.
AS 100
AS 1001 AS 1002
EBGP
IBGP