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The CNA system must be a route reflector client to all of the edge routers that will operate within the CNA system’s sphere of influence.
When multiple edge routers are being configured for route reflection, a BGP cluster ID is required. The number can be either a 32 bit integer or an IP address, but you must use the same number on each device on which routing tables are to be placed under the direction of the CNA system.
bgp cluster-id 88
Now define the parameters of the IBGP peering configuration from the edge router to the CNA system:
neighbor 172.16.6.14 remote-as 65002 neighbor 172.16.6.14 description IBGP to CNA neighbor 172.16.6.14 route-reflector-client neighbor 172.16.6.14 soft-reconfiguration inbound neighbor 172.16.6.14 weight 200
The remote-as command identifies the peering as IBGP (because the remote AS number matches the AS number in the bgp command).
The description command adds some descriptive text to the configuration.
The route-reflector-client command designates the CNA system as a BGP route reflector client.
The soft-reconfiguration command allows the CNA system to make changes to the BGP configuration without a session reset.
The weight command assigns a high value to the CNA system, which causes the edge router to prefer the CNA system’s routing assertions over the natural BGP route selection. This assignment is non-transitive, which means that the weighting is not communicated to other IBGP or EBGP peers. The weight attribute is local to this router only. In the example, weight is set to 200. The actual setting will be dependent on your local policies. The weight value should be high enough to prevail over those policies, but see the discussion of weights in Chapter 4: High Availability of the CNA Adaptive Path Controller Guide.
NOTE: The CNA system has a built-in precaution that prevents its route assertions from leaking beyond your edge router’s borders. The no-export attribute is always set in all CNA BGP routing updates. This is not user configurable. This attribute prohibits the router from passing routes that it has learned from the CNA system to routers outside the local AS.
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