[nsp] ospf default routes and bgp injection

[Nick Kraal]

Neil,

Your last point made on the 'gotcha' is a good and valid one --especially
when you have network allocations for ISDN dial/backup customers and they
then decide to dial to another PoP. This was one of the arguments put
forward. So there will always be a small number (hopefully) of unavoidable
IP blocks running around on the IGP.

-nick/

----- Original Message ----- 
From: "Neil J. McRae" <neil at COLT.NET>
To: <mtinka at africaonline.co.sz>; "'Oliver Boehmer (oboehmer)'"
<oboehmer at cisco.com>; "'Nick Kraal'" <nick at arc.net.my>;
<cisco-nsp at puck.nether.net>
Sent: Wednesday, April 07, 2004 11:35 PM
Subject: RE: [nsp] ospf default routes and bgp injection


>
> > As Nick mentioned, using OSPF to carry your infrastructure
> > networks (Loopback interface IP's mostly) and using iBGP to
> > carry your internal and customer prefixes is quite a scalable
> > approach.
> >
> > Nick (sorry to post this in Oliver's thread), you're right. I
> > don't think I have seen a supporting document anywhere yet
> > (there could be, though), but this is something that has been
> > presented and agreed on multiple operators forums and
> > seminars that I've been a part of.
> >
> > It scales quite well and offers more features in terms of
> > filtering, flexibility and all. Just FYI, this is how I run
> > my backbone.
>
> Over the past year or so we have been integrating the many
> COLT ASes into AS8220. We have just completed one of the most
> difficult parts which was caused by the former network carrying
> customer routes in IGPs. Around 5000 routes where in the IGP
> and every time we tried to do anthing including minor stuff
> IGP flaps killed us. We migrated these routes into BGP4 and
> management of the network became a million times simpler.
>
> One gotcha is that you need to be aware of how you would do
> high availiblity services, such as ISDN backup, dual homing
> etc.
>
> Neil.
>
>