Merit Network
Can't find what you're looking for? Search the Mail Archives.
  About Merit   Services   Network   Resources & Support   Network Research   News   Events   Home

Discussion Communities: Merit Network Email List Archives

North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

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 [mailto:mleber@he.net]
Sent: Saturday, September 14, 2002 4:19 PM
To: Lupi, Guy
Cc: 'nanog@merit.edu'
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 10.10.10.2 default-originate
 neighbor 10.10.10.2 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.

Mike.

+----------------- H U R R I C A N E - E L E C T R I C -----------------+
| Mike Leber           Direct Internet Connections   Voice 510 580 4100 |
| Hurricane Electric     Web Hosting  Colocation       Fax 510 580 4151 |
| mleber@he.net                                       http://www.he.net |
+-----------------------------------------------------------------------+




Discussion Communities


About Merit | Services | Network | Resources & Support | Network Research
News | Events | Contact | Site Map | Merit Network Home


Merit Network, Inc.