Re: Route Aggregation

John Krawczyk <jkrawczy@baynetworks.com> Wed, 24 May 1995 15:42 UTC

Message-Id: <199505241517.AA54395@interlock.ans.net>
Date: Wed, 24 May 95 11:17:36 EDT
Sender: ietf-archive-request@IETF.CNRI.Reston.VA.US
From: John Krawczyk <jkrawczy@baynetworks.com>
To: bgp@ans.net
Subject: Re: Route Aggregation
In-Reply-To: <199505241443.AA33468@interlock.ans.net>
References: <199505241443.AA33468@interlock.ans.net>
Reply-To: jkrawczy@baynetworks.com

   On Wed, 24 May, Radha Gowda (rxg@joplin.proteon.com) wrote:

   Can anybody tell me if my understanding of the AS_PATH aggregation
   rules are correct?
   
   2. 
       
     [SEQ  #3  0002  0005  0004] 
                                ==> [SEQ #3 0001 0004 0002] [SET #2 0003  0005]
     [SEQ  #3  0002  0003  0004] 

I believe you've violated this part of section 9.2.4.2:

         - for any tuple X of the type AS_SEQUENCE in the aggregated
         AS_PATH which precedes tuple Y in the aggregated AS_PATH, X
         precedes Y in each AS_PATH in the initial set which contains Y,
         regardless of the type of Y.

I.e., 0002 cannot precede 0005 or 0003 in the aggregated path.
   

I think that the following two AS paths are the legal choices:

	[SEQ #2 0001 0004] [SET #3 0003  0005  0002]

(this is what the default algorithm further down in section 9.2.4.2
would give you) or:

	[SEQ #2 0001 0004] [SET #2 0003  0005] [SEQ #1 0002]

-jj

Route Aggregation Radha Gowda
Re: Route Aggregation John Krawczyk
Re: Route Aggregation Paul Traina