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RE: BGP Default Route

  • From: Lupi, Guy
  • Date: Sat Sep 14 16:30:44 2002

I see what you are saying, and I understand that the default route would be
originated per neighbor, or per peer group for all neighbors within that
peer group.  My biggest concern is that if the aggregation router with this
configuration was to lose connectivity back to the routers which provide it
with external routing information, it would still announce the default to
that neighbor.  Do you feel that this is an acceptable risk, taking into
consideration that the aggregation router has redundant connectivity to
those routers that provide it with it's external routing information and it
is highly unlikely that the router would lose it's view of the world?

-----Original Message-----
From: Mike Leber []
Sent: Saturday, September 14, 2002 4:19 PM
To: Lupi, Guy
Cc: ''
Subject: Re: BGP Default Route

On Sat, 14 Sep 2002, Lupi, Guy wrote:
> I was wondering how people tend to generate default routes to customers
> running bgp.

Typically you would only originate default via BGP to a customer that
isn't taking a full view.

 neighbor default-originate
 neighbor filter-list 9 out

ip as-path access-list 9 deny ^.*$

>  Is it from the aggregation router that customers are directly
> connected to, or from one or more core/border routers?

In the example above the default originate is done via a specific BGP
session, so it isn't router wide on either core or border routers.

> If one is using a default route to null 0...

I'll leave the rest of this for somebody else to answer.


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