Re: AS-wide Unique BGP Identifier

[Enke Chen <[e-mail]>]

Hi, Jeff:

> Date: Thu, 20 Dec 2001 16:29:12 -0500
> From: Jeffrey Haas <[e-mail]>
> To: Enke Chen <[e-mail]>
> Cc: [e-mail], [e-mail], [e-mail],
> 	[e-mail]
> Subject: Re: AS-wide Unique BGP Identifier
> Message-ID: <[e-mail]>
> 
> On Thu, Dec 20, 2001 at 12:25:19PM -0800, Enke Chen wrote:
> > 4.3. Connection Collision Resolution
> > 
> >    For a BGP speaker that supports the AS-wide Unique BGP Identifier,
> >    the procedures for connection collision resolution are extended as
> >    follows to deal with the case in which the two BGP speakers share the
> >    same BGP Identifier (thus it is only applicable to an external peer):
> 
> Why would it only be applicable to an external peer?

Because the internal peers need to have unique BGP Identifiers in order
to bring up the session. So you do not run into this situation for IBGP.

> 
> >      If the BGP Identifiers of the peers involved in the connection
> >      collision are identical, then the connection initiated by the BGP
> >      speaker with the larger AS number is preserved.
> 
> So, if you are AS 1, and you try to peer with AS 2, and you have
> an internal peer with 1.1.1.1 as its ID and AS 2 has 1.1.1.1, you'll
> drop your peering session with your internal peer?

No, these are two different peers. However, if the router AS1 also has
ID 1.1.1.1, then it can not bring up an internal peer with another
rotuer that has ID 1.1.1.1.

> 
> > 5. Remarks
> > 
> >    It is noted that a BGP Identifier allocated based on [BGP-4] fits the
> >    revised definition.
> 
> And should note that "when possible, a globally routable IP address
> should be used as it assists debugging."

Sure, we can add some text. Thanks. -- Enke

> 
> 
> -- 
> Jeff Haas 
> NextHop Technologies