Riverstone Networks RS Switch Router User Guide Release 8.0 16-37
BGP Configuration Guide BGP Configuration Examples
Notes on Using Route Reflection
•Two types of route reflection are supported:
-By default, all routes received by the route reflector from a client are sent to all internal peers
(including the client’s group, but not the client itself).
-If the no-client-reflect option is enabled, routes received from a route reflection client are
sent only to internal peers that are not members of the client's group. In this case, the client's
group must itself be fully meshed.
In either case, all routes received from a non-client internal peer are sent to all route reflection clients.
•Typically, a single router acts as the reflector for a cluster of clients. However, for redundancy, two
or more may also be configured to be reflectors for the same cluster. In this case, a cluster ID should
be selected to identify all reflectors serving the cluster, using the clusterid option. Gratuitous use
of multiple redundant reflectors is not advised, since it can lead to an increase in the memory
required to store routes on the redundant reflectors’ peers.
•No special configuration is required on the route reflection clients. From a client's perspective, a
route reflector is simply a normal IBGP peer. Any BGP version 4 speaker can be a reflector client.
•It is necessary to export routes from the local AS into the local AS when acting as a route reflector.
To accomplish this, routers R10 and R11 have the following line in their configuration files:
•If the cluster ID is changed, all BGP sessions with reflector clients will be dropped and restarted.
16.3.9 BGP Confederation Example
Figure16-11 shows a BGP configuration where a single AS (AS number 64705) is split into two sub-AS’s (64706 and
64707).
Figure 16-11Sample BGP confederation
ip-router policy redistribute from-proto bgp source-as 64901 to-proto bgp target-as
64901
AS 64705
AS 64902
AS 64707
AS 64706
AS 64901
BGP Confederation
R9
R8 R10 R11 R12 R13