Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 425)

Support for RFC 4456
Route reflection on Brocade devices is based on RFC 4456. This updated RFC helps eliminate routing
loops that are possible in some implementations of the older specification, RFC 1966. These instances
include:
• 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 device ID of the
device that originated the route. The route reflector sets this attribute only if this is the first time the
route is being reflected (sent by a route reflector).
• If a device receives a route with an ORIGINATOR_ID attribute value that is the same as the ID of the
device, the device discards the route and does not advertise it. By discarding the route, the device
prevents a routing loop.
• The first time a route is reflected by a device configured as a route reflector, the route reflector adds
the CLUSTER_LIST attribute to the route. Other route reflectors that receive the route from an IBGP
neighbor add their cluster IDs to the front of the routes CLUSTER_LIST. If the route reflector does
not have a cluster ID configured, the device adds its device ID to the front of the CLUSTER_LIST.
• If a device configured as a route reflector receives a route with a CLUSTER_LIST that contains the
cluster ID of the route reflector, the route reflector discards the route.
Configuration procedures for BGP4 route reflector
To configure a Brocade device to be a BGP4 route reflector, use either of the following methods.
NOTE
All configuration for route reflection takes place on the route reflectors, not on the clients.
Enter the following commands to configure a Brocade device as route reflector 1. To configure route
reflector 2, enter the same commands on the device that will be route reflector 2. The clients require no
configuration for route reflection.
device(config-bgp)# cluster-id 1
Syntax: [no] cluster-id num | ip-addr
The num and ip-addr parameters specify the cluster ID and can be a number from 1 - 4294967295, or
an IP address. The default is the device ID. You can configure one cluster ID on the device. All route-
reflector clients for the device are members of the cluster.
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.
To add an IBGP neighbor to the cluster, enter the following command:
device(config-bgp)# neighbor 10.0.1.0 route-reflector-client
Syntax: [no] neighbor ip-addr route-reflector-client
Support for RFC 4456
FastIron Ethernet Switch Layer 3 Routing Configuration Guide 425
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