BGP: next hop self

[vsabariraja]

Hi,

If it is necessary to configure neighbor command with next-hop-self on every inetral BGP routers (i am not asking about the router which connects two AS). If yes, how does it works in IBGP.

[paul driver]

Hello

The next hop is the ip address of the ebgp/ibgp router , that is what the neighbor command is stating towards the ebgp peer.

This is carried into ibgp domain by default- so if you have a external network  coming in your asn via a ebgp peer

then the internal ibgp peer will see the next-hop as the external asn address and if it dosnt have a path to this next-hop it will fail.

so by providing the next hop self command on the egbp/ibgp router facing the ibgp peer, then the internal ibgp peer will have a vaild next hop to reach the external route.

res

res

Paul

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml#bgpnexthop

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