Dell FCX624-E Laptop User Manual


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1018 PowerConnect B-Series FCX Configuration Guide
53-1002266-01
Optional configuration tasks
30
A cluster is a group of IGP routers organized into route reflectors and route reflector clients. You
configure the cluster by assigning a cluster ID on the route reflector and identifying the IGP
neighbors that are members of that cluster. All the configuration for route reflection takes
place on the route reflectors. The clients are unaware that they are members of a route
reflection cluster. All members of the cluster must be in the same AS. The cluster ID can be any
number from 0 through 4294967295. The default is the router ID, expressed as a 32-bit
number.
NOTE
If the cluster contains more than one route reflector, you need to configure the same cluster ID
on all the route reflectors in the cluster. The cluster ID helps route reflectors avoid loops within
the cluster.
A route reflector is an IGP router configured to send BGP route information to all the clients
(other BGP4 routers) within the cluster. Route reflection is enabled on all Dell BGP4 routers by
default but does not take effect unless you add route reflector clients to the router.
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.
NOTE
Route reflection applies only among IBGP routers within the same AS. You cannot configure a cluster
that spans multiple autonomous systems.
Figure 147 shows an example of a route reflector configuration. In this example, two Layer 3
Switches 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.