From: Petr Lapukhov (petr@internetworkexpert.com)
Date: Wed Jul 05 2006 - 13:05:16 ART
Yes, NSSA area is very special in few ways :)
1) Translating ABR election (highest RID)
2) Type 7->5 translation, which actually "recreates" LSAs at ABR
(that's why we can filter/summarize them at ABR, not only ASBR)
3) FA issues, and suppress-fa feature.
Above of all these, OSPF has lots of other features, like Type 3 LSA
filter for example. Make them all interacting and you can get amazing
and really funny things!
-- Petr Lapukhov, CCIE #16379 petr@internetworkexpert.comInternetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Outside US: 775-826-4344
2006/7/5, D.H. Williams <draythw@gmail.com>: > > Awesome list. I'm going to try a few of these out today (especially the > nssa techniques). I am extremely grateful for your professionalism and > knowledge in answering this and others questions. Very, very > appreciative! > > > D > > > On 7/5/06, Petr Lapukhov <petr@internetworkexpert.com> wrote: > > > > So just to summarize what's been said, the techniques we may use > > to filter *External* routing information with OSPF: > > > > 1) Local router > > > > 1.1) distribute-list (per-interface, based on prefixes), > > 1.2) distribute-list with route-map ( match next-hop, tag, > > interface). > > Match next-hop didn't work with prefix-list though, just > with > > ACL > > 1.3) Change cost/bandwidth in any way > > > > 2) Transit router, non-ABR > > > > 2.1) Change cost/bandwidth in any way > > 2.2) Max-metric lsa (similar to above) > > > > 3) Transit router, ABR > > > > 3.1) With NSSA "summary not-advertise", or change RID > > to influence translator election > > 3.1) Change cost/bandwidth in any way > > 3.3) Filter forward-address with NSSA and other cases, > > where FA is present (also, nssa suppress-fa may help here) > > > > There are also a number of ways to use virtual links to influence > routing > > decision, but this is getting complex already :) > > > > I can drop few examples a bit later, just too loaded with work now :( > > > > HTH > > -- > > Petr Lapukhov, CCIE #16379 > > petr@internetworkexpert.com > > > > Internetwork Expert, Inc. > > http://www.InternetworkExpert.com <http://www.internetworkexpert.com/> > > Toll Free: 877-224-8987 > > Outside US: 775-826-4344 > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html
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