[c-nsp] BGP and IGP

[David Barak]

--- 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.

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


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