BGP nexthop-self vs. EIGRP redistribution

Jack Bates jbates at brightok.net
Mon Mar 16 12:06:06 CDT 2009


phil at mindfury.net wrote:
> ...which is better?

Neither (both) is better, depending on the scenario. This is especially 
true when mixing in MPLS and other features.

> 
> My question is, which is the correct method of implementing this?  Should
> we be redistributing static and connected routes on our borders into IGP,
> and not using next-hop-self?  Or should we not redistribute and use
> next-hop-self?

next-hop-self seems to remain more stable overall. In some scenarios I 
believe it is even required (just as not using it is required in other 
scenarios). For your deployment, I'd say you are open to choose either, 
and next-hop-self would be the more stable of the two. The largest issue 
with NOT using next-hop-self that I have seen is the effect it has when 
that IGP route for the next hop disappears. BGP tends to be more 
graceful about removing routes via iBGP then handling routes locally 
when they are suddenly unreachable via IGP.

Another benefit of next-hop-self is the fact that the IGP doesn't have 
to be overly enlarged when you have a large network (injecting hundreds 
or thousands of links into IGP). With OSPF/ISIS in a flat (single area) 
topology utilizing MPLS across the core, you would prefer stability in 
the link state database. Each edge network you place in IGP increases 
the chances of a database change, and in critical outages, they increase 
the number of changes that must be made.


-Jack






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