From: Adam Crisp (adam.crisp@totalise.co.uk)
Date: Fri Oct 11 2002 - 10:24:18 GMT-3
this is all about Administrative distances and the fact that redistribution
between protocols only works if the route makes the Forwarding information
base.
Example
If you have an EIGRP AS, with some external routes, the distance for those
routes is 170 - an EIGRP external...
If you then have two routers, both running EIGRP and both running OSPF
Both routers are in the same EIGRP AS and the same OSPF area.
Both routers are doing mutual redistribution and route maps are in place to
prevent routing loops.
If you then look at the OSPF database, you'll see that only one of the
Routers is advertiseing the external eigrp routes?
If you kill the router that is advertising the routes - then the other one
immediatly start advertising the route.
Why?
When the 1st router redistributes from EIGRP to OSPF, OSPF then has the
route - with an external ospf distance of 110 !
the second router is then presented with two routes to the external, 1 -
eigrp 170, or ospf 110,
the ospf route makes the FIB, and that router will not redistribute the
route!
When the first router is killed, then the second router has one option -
eigrp 170, and this route makes the FIB, and this route is then
redistributed!
Hope this makes sense,
I your example, your router has:
OSPF - AD 110
EIGRP - AD 90 (ext 170)
connected = AD - 0
( and static is AD = 1)
when you redistribute the connected into eigrp, the router has two routes to
the interface to consider, Eigrp AD-170 and Connected - AD-0
the connected route makes the FIB.
As the EIGRP route does not make the FIB, then this route will not be
redistributed into OSPF
Good luck
Adam
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
chenyan
Sent: 11 October 2002 05:06
To: ccielab
Subject: redistribute problem
hi,all
(eigrp)---R-----(ospf)
|
|
E0
mutual redistribution is implemended on R between eigrp and ospf,then I
redistribute connected with E0 into eigrp, is it possible that I cant see
the connected network in the ospf bacause of the mutual redistribution, but
why?
Thanks
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