It depends. As you know, in OSPF, route preference is: internal, inter-area, external, meaning that inter-area routes will always be preferred over external ones. So, from that perspective, you are still "protected" from looping OSPF-originated routes. However, when you redistribute something into OSPF and that travels away from OSPF to other domains and comes back, at the redistribution point, metric may change and you could theoretically introduce a loop.
I don't want to criticize, but your diagram is not entirely clear to me and I was answering just in general. Now, trying to configure redistribution from your diagram, this is a way I'd do it. The solution below will probably work, but make sure you are running "debug ip routing". In a case you are still having a loop caused by triple redistribution on R3 (unlikely, but possible), you may want to ensure "per-router" tags, where you will identify each redistribution router with a separate tag and control the redistributed routes based on that. R2 and R3: route-map O2E deny 10 match tag 90 ! route-map O2E permit 20 match tag 120 set tag 120 ! route-map O2E permit 30 set tag 110 ! route-map E2O deny 10 match tag 110 ! route-map E2O permit 20 match tag 120 set tag 120 ! route-map E2O permit 30 set tag 90 ! R4: route-map O2E deny 10 match tag 90 ! route-map O2E permit 20 match tag 120 set tag 120 ! route-map O2E permit 30 set tag 110 ! route-map O2R deny 10 match tag 120 ! route-map O2R permit 20 match tag 90 set tag 90 ! route-map O2R permit 30 set tag 110 ! route-map E2O deny 10 match tag 110 ! route-map E2O permit 20 match tag 120 set tag 120 ! route-map E2O permit 30 set tag 90 ! route-map E2R deny 10 match tag 120 ! route-map E2R permit 20 match tag 110 set tag 110 ! route-map E2R permit 30 set tag 90 ! route-map R2O deny 10 match tag 110 ! route-map R2O permit 20 match tag 90 set tag 90 ! route-map R2O permit 30 set tag 120 ! route-map R2E deny 10 match tag 90 ! route-map R2E permit 20 match tag 110 set tag 110 ! route-map R2E permit 30 set tag 120 ! SW1: route-map O2R deny 10 match tag 120 ! route-map O2R permit 20 match tag 90 set tag 90 ! route-map O2R permit 30 set tag 110 ! route-map R2O deny 10 match tag 110 ! route-map R2O permit 20 match tag 90 set tag 90 ! route-map R2O permit 30 set tag 120 ! -- Marko Milivojevic - CCIE #18427 Senior Technical Instructor - IPexpert FREE CCIE training: http://bit.ly/vLecture Mailto: [email protected] Telephone: +1.810.326.1444 Web: http://www.ipexpert.com/ On Mon, Sep 13, 2010 at 18:17, Aryan <[email protected]> wrote: > Dear IPX team, > > On last Friday I attended IPX V Lecture on IGP Redistribution, Going further > I have drawn a topology, now can you please share how we will approach this > topology with "Route Tag. Retag and filter technique <clock wise & anti > clock wise> " mentioned during V lecture. > > Logical explanation will be enough. > > Also In diagram I referred OSPF domain not Area, idea being was that there > were mulitple Areas around CORNERS connecting back to Area 0 though varius > techniques like tunnels, through ABR, ASBR, Virtual Links etc. > > So you can very well consider this OSPF domain As Backbone area, but will > other areas across different locations effect Redistribution ? > > http://imageshare.web.id/images/is9oi9bc53iyochgi2n.png > > > Thanks! > Aryan > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
