Configuring Next-Hop Processing

Routes sent by BGP speakers include the next-hop attribute. The next hop is the IP address of a node on the network that is closer to the advertised prefix. Routers that have traffic destined for the advertised prefix send the traffic to the next hop. The next hop can be the address of the BGP speaker sending the update or of a third-party node. The third-party node does not have to be a BGP speaker.

The next-hop attributes conform to the following rules:

• The next hop for EBGP sessions is the IP address of the peer that advertised the route.
• The next hop for IBGP sessions is one of the following:
  • If the route originated inside the AS, the next hop is the IP address of the peer that advertised the route.
  • If the route originated outside the AS—that is, it was injected into the AS by means of an EBGP session—the next hop is the IP address of the external BGP speaker that advertised the route.
• For routes advertised on multiaccess media—such as Frame Relay, ATM, or Ethernet—the next hop is the IP address of the originating router’s interface that is connected to the medium.

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