Alcatel-Lucent 9000 Switch User Manual


 
Configuring BGP BGP Overview
OmniSwitch 6800/6850/9000 Advanced Routing Configuration Guide December 2007 page 4-9
Route Reflectors
Route reflectors are useful if the internal BGP mesh becomes very large. A route reflector is a concentra-
tion router for other BGP peers in the local network, acting as a focal point for internal BGP sessions.
Multiple client BGP routers peer with the central route server (the reflector). The router reflectors then
peer with each other. Although BGP rules state that routes learned via one IBGP speaker cannot be adver-
tised to another IBGP speaker, route reflection allows the router reflector servers to “reflect” routes,
thereby relaxing the IBGP standards.
Note. This feature, which is used to minimize the number of IBGP sessions in an AS is not supported in
the IPv6 BGP environment.
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 4-40.
The following illustration demonstrates this concept:
BGP Reflector 2
BGP Client 4
BGP Client 3
BGP Client 2
BGP Client 1
BGP Client 5
BGP Client 6
AS 100 with Route Reflection
BGP Reflector 1