BGP Large Scale BGP Route Reflectors with Clusters

BGP Route Reflection: An Alternative to Full Mesh Internal BGP (IBGP)- Part II

           - Larger scale BGP designs cannot be serviced by only a single RR

• Single RR is a single point of failure

           - RR "clusters" allow redundancy and hierarchy

• Cluster is defined by the clients a RR serves

• RRs in the same cluster use the same Cluster-ID

           - Inter-Cluster peerings between RRs can be client or non-client peerings

• Depends on redundancy design

Video Demonstration

from: Cisco IOS IP Routing: BGP Command Reference

bgp cluster-id

To configure the cluster ID if the BGP cluster has more than one route reflector, use the bgp cluster-id command in router configuration mode. To remove the cluster ID, use the no form of this command.

bgp cluster-id cluster-id

no bgp cluster-id cluster-id

Syntax Description

cluster-id

Cluster ID of this router acting as a route reflector; maximum of 4 bytes.

Defaults

The router ID of the single route reflector in a cluster

Command Modes

Router configuration

Command History

Release	Modification
11.0	This command was introduced.

Usage Guidelines

Together, a route reflector and its clients form a cluster.

Usually a cluster of clients will have a single route reflector. In that case, the cluster is identified by the router ID of the route reflector. In order to increase redundancy and avoid a single point of failure, a cluster might have more than one route reflector. In this case, all route reflectors in the cluster must be configured with the 4-byte cluster ID so that a route reflector can recognize updates from route reflectors in the same cluster.

If the cluster has more than one route reflector, use this command to configure the cluster ID.

Examples

In the following example, the local router is one of the route reflectors serving the cluster. It is configured with the cluster ID to identify the cluster.

router bgp 5

 neighbor 198.92.70.24 route-reflector-client

 bgp cluster-id 50000

Related Commands

Command	Description
bgp client-to-client reflection	Restores route reflection from a BGP route reflector to clients.
neighbor route-reflector-client	Configures the router as a BGP route reflector and configures the specified neighbor as its client.
show ip bgp	Displays entries in the BGP routing table.

Files:
Topology
Configs
BGP Configuration