[c-nsp] BGP and IGP

[Kevin Barrass]

Hi

Thank you for the below, the only problem we are having with this is if
a BGP router on our network fails because we still have a default route
via another BGP router even though the loopback address drops from the
IGP the iBGP peering stays up for 3 mins till it times out as it thinks
it can still get to the loopback via the default route.
The only way around I could find was to redistribute 0.0.0.0/0 from eBGP
into EIGRP to speed up re-convergence as the redistributed 0.0.0.0/0 is
preferred over the iBGP one but this seems to go against all
recommendations I can find online.
Luckily all of this is still on a test network so isn't live yet we just
want to make sure we do things correctly.

Regards

Kev


-----Original Message-----
From: Peter Nyamukusa [mailto:petern at africaonline.co.sz] 
Sent: 02 November 2007 07:58
To: thegameiam at yahoo.com; cisco-nsp at puck.nether.net; Kevin Barrass
Subject: RE: [c-nsp] BGP and IGP

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp- 
> bounces at puck.nether.net] On Behalf Of David Barak
> Sent: 01 November 2007 04:04 PM
> To: cisco-nsp at puck.nether.net; Kevin Barrass
> Subject: Re: [c-nsp] BGP and IGP
> 
> 
> 
> 
> 
> --- On Thu, 11/1/07, Kevin Barrass <K.J.Barrass at leeds.ac.uk> wrote:
> 
> > From: Kevin Barrass <K.J.Barrass at leeds.ac.uk>
> > Subject: [c-nsp] BGP and IGP
> > To: cisco-nsp at puck.nether.net
> > Date: Thursday, November 1, 2007, 8:05 AM Hi
> >
> > On our network we currently don't need to run an IGP and use static 
> > routes. All the routers run BGP and are in a full iBGP mesh.
> >
> > We are now in a position were we will need to have routers on our 
> > network running an IGP and no BGP such as EIGRP. What I am wondering

> > is do ppl in this situation redistribute from BGP into EIGRP the 
> > default route they are receiving from the eBGP peer with there 
> > provider or is there an other way of doing this.
> >
> > Any Advise on what is best practice on this much appreciated.

If you intend on being a transit network I would recommend running BGP
on all your routers and an IGP to carry your loopback IPs, this is a
more scalable solution

Regards
--------------------
Peter Nyamukusa CCIP, JNCIS-ER, MCSE

> 
> In general terms, I recommend making sure that routers with real 
> decisions to make have all of the information.  So a place to start 
> would be
> 
> ISPs <=> BGP routers <=> iBGP + EIGRP routers <=> EIGRP only routers
> 
> Where the iBGP + EIGRP router injects an EIGRP default route.  I don't

> recommend redistributing from BGP to an IGP, because you get a tight 
> coupling where an ISP ripple gets passed all the way down to the LAN 
> routers.
> 
> Hope that helps,
> 
> David Barak
> Need Geek Rock?  Try The Franchise:
> http://www.listentothefranchise.com
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around 
> http://mail.yahoo.com _______________________________________________
> 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/