RE: BGP MED

From: Bhisham Bajaj (bhishambajaj@xxxxxxxxx)
Date: Sat Apr 06 2002 - 02:27:49 GMT-3


   
There are two different tables

One is the routing table and the other is a bgp table

Ok with the routing table it works this way

The first thing is that if u have a network with the
same mask learned from different ways then

Then the less admin distance route is put in the
routing table

If booth the routes r learned from the same routing
protocol then the less metric route is put in the
table

With bgp what happens is that

The routes are put in the bgp table first where based
on some things like the med, local p, weight, router
id, origin, etc one route is preferred route and is
marked as > this route is put in the routing table

So that is if a router has a route learned by ebgp and
ibgp and the ibgp route is the preferred route in the
bgp table based on the weight or med or local pref
then the ibgp route though has a adm distance of 200
will be installed in the routing table

So I think that with bgp the ad of 20 or 200 will not
play a role unless there is some other routing
protocol that is also learning the same route

That is if I am learning the route from ebgp & ibgp &
ospf then if in the bgp table the ebgp route is the
preferred route it will get installed in the routing
table
If in the bgp table the ibgp route is the preferred
route then it will try to make it to the routing table
but will not get installed as the ospf route will get
installed.

Can some one PS confirm what I am thinking is the way
that it works or there is some other saga to it

TIA

BB

--- "David Lee Steele, Jr." <d.steele2@comcast.net>
wrote:
> Oh yeah. I guess you would need to use the neighbor
> backdoor command.
>
> David
>
> -----Original Message-----
> From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> Manny Gonzalez
> Sent: Friday, April 05, 2002 8:42 PM
> To: Peter Dostal
> Cc: ccielab@groupstudy.com
> Subject: Re: BGP MED
>
> What about the ADMIN DISTANCE? Don't forget that
> eBGP is 20 and iBGP is
> 200
>



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