BGP ORF
- Prevents the local device from receiving a large number of unnecessary routes.
- Reduces CPU usage of the local device.
- Simplifies the configuration of BGP peers.
- Improves link bandwidth efficiency.
Application Scenarios
BGP ORF applies to the scenario where a device wants BGP peers to send only required routes, and BGP peers do not want to maintain different export policies for different devices.
As shown in Figure 9-12, after negotiating the prefix-based ORF capability with RouterB, RouterA adds the local prefix-based import policies to a Route-refresh message and sends the message to RouterB. RouterB constructs export policies based on the received Route-refresh message and sends required routes to RouterA using a Route-refresh message. RouterA receives only required routes, and RouterB does not need to maintain routing policies. This reduces the configuration workload.
As shown in Figure 9-13, there is a route reflector (RR) in AS 100. RouterA and RouterB are the clients of the RR. RouterA, RouterB, and the RR negotiate the prefix-based ORF capability. RouterA and RouterB then add the local prefix-based import policies to Route-refresh messages and send the messages to the RR. The RR constructs export policies based on the received import policies and reflects required routes in Route-refresh messages to RouterA and RouterB. RouterA and RouterB receive only required routes, and the RR does not need to maintain routing policies. This reduces the configuration workload.