784 BigIron RX Series Configuration Guide53-1001986-01Filtering26• If a device receives a route whose ORIGINATOR_ID attribute has the value of the device’s ownrouter ID, the device discards the route and does not advertise it. By discarding the route, thedevice prevents a routing loop.• The first time a route is reflected by a device configured as a route reflector, the route reflectoradds the CLUSTER_LIST attribute to the route. Other route reflectors who receive the routefrom an IBGP neighbor add their cluster IDs to the front of the route’s CLUSTER_LIST. If theroute reflector does not have a cluster ID configured, the device adds its router ID to the frontof the CLUSTER_LIST.• If the device configured as a route reflector receives a route whose CLUSTER_LIST contains theroute reflector’s own cluster ID, the route reflector discards the route and does not forward it.Configuration proceduresNOTEAll configuration for route reflection takes place on the route reflectors, not on the clients.Enter the following commands to configure a device as route reflector 1 in Figure 26.4 onpage 26-42. To configure route reflector 2, enter the same commands on the device that will beroute reflector 2. The clients require no configuration for route reflection.BigIron RX(config-bgp)# cluster-id 1BigIron RX(config-bgp)# neighbor 10.0.1.0 route-reflector-clientBigIron RX(config-bgp)# neighbor 10.0.2.0 route-reflector-clientSyntax: [no] cluster-id | The | parameter specifies the cluster ID and can be a number from 1 –4294967295 or an IP address. The default is the router ID. You can configure one cluster ID onthe router. All route-reflector clients for the router are members of the cluster.NOTEIf the cluster contains more than one route reflector, you need to configure the same cluster ID onall the route reflectors in the cluster. The cluster ID helps route reflectors avoid loops within thecluster.To add an IBGP neighbor to the cluster, enter the following command.Syntax: neighbor route-reflector-clientFor more information about the neighbor command, refer to “Configuring BGP4 neighbors” onpage 761 and “Configuring a BGP4 peer group” on page 768.FilteringThis section describes the following:• “Filtering AS-paths” on page 785• “Filtering communities” on page 788• “Defining and applying IP prefix lists” on page 789• “Defining neighbor distribute lists” on page 790• “Defining route maps” on page 791
