Subject: LSA 5 (7) filtering

From: Arkadiusz Binder <[email-masked]>
Date: Thu, 18 Dec 2003 14:18:40 +0100

I wanted to filter LSA type 5 routes, but read old topics, where it is
assumed that it is not OK.
I use OSPF in Wireless Network connectivities too.

I'm peering one OSPF domain across my ISP-partner network. Sometimes i want
to not permit some routes to be injected into some places (i want them to be
destroyed, and sent by partner's default route instead of that peering link
with OSPF network).

I think that it is possible to achieve target by using NSSA type.

But at the point i can't find nowhere a possibility to filter LSA7 (or LSA5)
type routes .

If   A-----B--NSSA--C--D

router A is ASBR with injecting 1.1.1.1/24 as TYPE5
i don't want router C knows that route.

At the moment, router C use fake route=his_default route to router D (Router
D is announcing this route via RIP... etc)

Is it a target of working group or is it a target of soft implementation ?

A.Binder

---

From: Acee Lindem <[email-masked]>
Date: Thu, 18 Dec 2003 11:03:57 -0500

> But at the point i can't find nowhere a possibility to filter LSA7 (or LSA5)

RFC 3101 defines how router B or C can easily control what type 7 routes are
aggregated or prevented from being advertised outside the NSSA. There is
no provision for LSA filtering. Since an IGP is typically under a single
administrative domain it would be better not to advertise the LSAs you
don't want on the originator.

-- 
Acee