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BGP next hop recursive resolution using other BGP routes

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BGP next hop recursive resolution using other BGP routes

By default, BGP routes are not considered when a BGP next hop requires recursive resolution. They are considered when recursive-next-hop is enabled. Recursive resolution will resolve to one level.

To consider BGP routes for recursive resolution of next hops:
config router bgp
    set recursive-next-hop enable
end

Example

To see the change in the routing table when the option is enabled:
  1. Check the BGP routing table:

    # get router info routing-table bgp
    Routing table for VRF=0
    B       10.100.1.4/30 [200/0] via 10.100.1.14 (recursive is directly connected, R560), 00:02:06
  2. Enable BGP routes for recursive resolution of next hops:

    config router bgp
        set recursive-next-hop enable
    end
  3. Check the BGP routing table again:

    # get router info routing-table bgp
    Routing table for VRF=0
    B       10.100.1.4/30 [200/0] via 10.100.1.14 (recursive is directly connected, R560), 00:02:15
    B       172.16.203.0/24 [200/0] via 10.100.1.6 (recursive via 10.100.1.14, R560), 00:00:06

    The second BGP route's next hop is now recursively resolved by another BGP route.

BGP next hop recursive resolution using other BGP routes

By default, BGP routes are not considered when a BGP next hop requires recursive resolution. They are considered when recursive-next-hop is enabled. Recursive resolution will resolve to one level.

To consider BGP routes for recursive resolution of next hops:
config router bgp
    set recursive-next-hop enable
end

Example

To see the change in the routing table when the option is enabled:
  1. Check the BGP routing table:

    # get router info routing-table bgp
    Routing table for VRF=0
    B       10.100.1.4/30 [200/0] via 10.100.1.14 (recursive is directly connected, R560), 00:02:06
  2. Enable BGP routes for recursive resolution of next hops:

    config router bgp
        set recursive-next-hop enable
    end
  3. Check the BGP routing table again:

    # get router info routing-table bgp
    Routing table for VRF=0
    B       10.100.1.4/30 [200/0] via 10.100.1.14 (recursive is directly connected, R560), 00:02:15
    B       172.16.203.0/24 [200/0] via 10.100.1.6 (recursive via 10.100.1.14, R560), 00:00:06

    The second BGP route's next hop is now recursively resolved by another BGP route.