[nsp] ospf default routes and bgp injection

[Nick Kraal]

Mark,

The arguments presented are definitely valid. Scalability and convergence on
top of the list. But some folks like to see documents/white papers from the
vendors to be convinced. Well thanks you all for the input.

Regards,

-nick/

----- Original Message ----- 
From: "Mark Tinka" <mtinka at africaonline.co.sz>
To: "'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 5:05 PM
Subject: RE: [nsp] ospf default routes and bgp injection


> cisco-nsp-bounces at puck.nether.net wrote:
> > Nick,
> >
> > I think it really depends on what you want to achieve and wich IGP
> > you're using. As general arguments:
> >
> > 1) customer routes in IGP don't scale. While OSPF/ISIS on modern
> > platforms (RISC CPU's) works just fine with 5000+ routes in your IGP,
> > scaling to 10000 and above might be a challenge
>
> 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.
>
> >
> > 2) The more routes you carry in your IGP, the longer PRC takes
> > installing the routes in your RIB. This will be in issue if you want
> > to tune your IGP for faster (i.e. sub-second) convergence
> >
> > I think one can find addtl. arguments if your specific network and
> > routing topology is taken into account.
> >
> > oli
> >
> > ----Original Message----
> > From: cisco-nsp-bounces at puck.nether.net
> > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Nick Kraal
> > Sent: Dienstag, 6. April 2004 14:45 To: cisco-nsp at puck.nether.net
> > Subject: Re: [nsp] ospf default routes and bgp injection
> >
> >> Following up on this one. We all know that the IGP of choice used
> >> should carry only infrastructure networks and kept as small as
> >> possible. The rest should be announced via iBGP. Is there a document
> >> that explains this rationale clear --having some difficulty
> >> convincing some folks.
> >>
> >> Thanks in advance,
> >>
> >> -nick/
> >>
> >> ----- Original Message -----
> >> From: "Gert Doering" <gert at greenie.muc.de>
> >> To: "Christopher J. Wolff" <chris at bblabs.com>
> >> Cc: <cisco-nsp at puck.nether.net>
> >> Sent: Thursday, April 01, 2004 5:49 AM
> >> Subject: Re: [nsp] ospf default routes and bgp injection
> >>
> >>
> >>> Hi,
> >>>
> >>> On Wed, Mar 31, 2004 at 09:58:12AM -0700, Christopher J. Wolff
> >>> wrote:
> >>>> I've considered ibgp as an end-to-end solution however never went
> >>>> so far as to implement it.
> >>>
> >>> Completely overkill in this network.  If there's no BGP speaker
> >>> "down the road", there is not much use in having all those routers
> >>> actually carry BGP information.
> >>>
> >>>> My concern is making sure that the entire routing table isn't
> >>>> propagated all the way to the edge device, which could be
> >>>> something minimal like a 2611XM.  Any thoughts?  Thank you for
> >>>> your advice.
> >>>
> >>> Have the BGP speakers distribute an OSPF (or EIGRP, or even RIP :) )
> >>> default route to the smaller boxes.
> >>>
> >>> gert
> >>> --
> >>> USENET is *not* the non-clickable part of WWW!
> >>>
> >> //www.muc.de/~gert/
> >>> Gert Doering - Munich, Germany gert at greenie.muc.de
> >>> fax: +49-89-35655025
> >> gert at net.informatik.tu-muenchen.de
> >>> _______________________________________________
> >>> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> >>> https://puck.nether.net/mailman/listinfo/cisco-nsp
> >>> archive at http://puck.nether.net/pipermail/cisco-nsp/
> >>>
> >>
> >> _______________________________________________
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> >
> > _______________________________________________
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>
> Regards,
>
> Mark Tinka
> Technical Manager, Africa Online Swaziland
>