Enable Next-hop Recursion for BGP4

With next-hop recursion enabled, a device can find the IGP route to the next hop for a BGP4 route.

1. Access global configuration mode.
   

   device# configure terminal

2. Access BGP configuration mode.
   

   device(config)# router bgp

3. Access address-family IPv4 unicast configuration mode.
   

   device(config-bgp-router)# address-family ipv4 unicast

4. Enable recursive next-hop lookups.
   

   device(config-bgp-ipv4u)# next-hop-recursion