From: Joseph Brunner (joe@affirmedsystems.com)
Date: Thu May 08 2008 - 13:09:03 ART
Why not tag the routes earlier on in the OSPF network?
Then the route-map can match tags from OSPF and set bgp attributes
accordingly?
I would do this though (if you can)
Put the ospf facing interface into a vrf.
On the bgp config for "address-family ipv4 vrf 9999" you can redistribute
into bgp and match ospf routes types you want to redistribute. The upstream
interface on the CE can also be in this VRF and not know it. ;)
_____
From: Luan Nguyen [mailto:luan.m.nguyen@gmail.com]
Sent: Thursday, May 08, 2008 11:01 AM
To: Joseph Brunner
Cc: ccielab@groupstudy.com
Subject: Re: Prepend routes redistribute from OSPF to BGP
Well, it's just between the PE and the CE so it's not that bad :)
The operation folks refuse to work with big prefix-list. They want a
"dynamic" solution. So each time the customer adds a network into OSPF, you
don't have to create another prefixes.
The problem is that i see little options matching IGP when comes to BGP
route-map.
Just when you think route redistribution in the lab is bad...you meet the
real 2 headed monter: customer's demands and support's stubborness.
-lmn
On Wed, May 7, 2008 at 10:59 PM, Joseph Brunner <joe@affirmedsystems.com>
wrote:
I would vote against redistributing an igp into bgp... everytime someone
does a "clear ip ospf process" millions of routers around the world waste
cpu time - THANKS!!!
A better idea is if this is the ONLY place where these blocks will be
advertised to bgp, just redistribute static's to BGP (the statics will be
held down with ip route w.x.y.z 255.255.x.0 null0 254
Many big ISP's do this.
Since you are going to prepend you can just write up some big prefix-lists
and match in them in route map sequences for the as path prepends.
Nothing fancy... I have seen 500 networks done this way... no biggie.
-Joe
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Luan
Nguyen
Sent: Wednesday, May 07, 2008 10:53 PM
To: ccielab@groupstudy.com
Subject: Prepend routes redistribute from OSPF to BGP
Hello,
Say i have a broadcast network of 10 OSPF routers. Each have a variety of
inter, intra, external routes.
One router peer BGP with an upstream. I want to advertise all OSPF networks
to the upstream. But i want a set of routes to have AS-PATH prepend. I
need to redistribute OSPF into BGP since the amount of routes are too many
to use network statements and too discontinuous to advertise summary routes.
Any idea how i could accomplish this?
TIA
-lmn
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