Dell PowerConnect B-RX Configuration Manual page 863

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NOTE
Route reflection applies only among IBGP routers within the same AS. You cannot configure a
cluster that spans multiple ASs.
Figure 26.4 shows an example of a route reflector configuration. In this example, two BigIron RX
devices are configured as route reflectors for the same cluster. The route reflectors provide
redundancy in case one of the reflectors becomes unavailable. Without redundancy, if a route
reflector becomes unavailable, its clients are cut off from BGP4 updates.
AS1 contains a cluster with two route reflectors and two clients. The route reflectors are fully
meshed with other BGP4 routers, but the clients are not fully meshed. They rely on the route
reflectors to propagate BGP4 route updates.
FIGURE 115
Support for RFC 2796
Route reflection is based on RFC 2796. This updated RFC helps eliminate routing loops that are
possible in some implementations of the older specification, RFC 1966.
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BigIron RX Series Configuration Guide
53-1001810-01
A route reflector client is an IGP router identified as a member of a cluster. You identify a
router as a route reflector client on the router that is the route reflector, not on the client. The
client itself requires no additional configuration. In fact, the client does not know that it is a
route reflector client. The client just knows that it receives updates from its neighbors and
does not know whether one or more of those neighbors are route reflectors.
Example route reflector configuration
AS 1
Cluster 1
Route
Reflector 1
Route
Reflector
Client 1
10.0.1.0
The device adds the route reflection attributes only if it is a route reflector, and only when
advertising IBGP route information to other IBGP neighbors. The attributes are not used when
communicating with EBGP neighbors.
A device configured as a route reflector sets the ORIGINATOR_ID attribute to the router ID of
the router that originated the route. Moreover, the route reflector sets the attribute only if this is
the first time the route is being reflected (sent by a route reflector).
Configuring route reflection parameters
Route
Reflector 2
EBGP
Route
Reflector
Client 2
10.0.2.0
AS 2
IBGP
IBGP
IBGP
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