On Mon, 16 Mar 2009, Jack Bates wrote:
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.
On smaller networks (where IGP size is not an issue), I could see some
benefit for redistributing connected to IGP and preserving the
next-hop for those interfaces which have a backup route through some
other interface. I.E: if the connected interface goes down, everyone
knows immediately that the nexthop is unusable, and you can start
using better working routes immediately, rather than waiting for the
routes being BGP WITHDRAWn.
Loopback and n-h-s seems to always make sense for those interfaces
which are singlehomed to that router (no redundancy) -- otherwise you
may want to consider which one is best.
--
Pekka Savola "You each name yourselves king, yet the
Netcore Oy kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings
