Subject: [Idr] Aggregation Question

From: "Eric P. Barrett" <[email-masked]>
Date: Fri, 2 Jul 2004 10:02:50 -0400

Hi,

According to draft 24, "Path attributes that have different type codes can not
be aggregated together."  Later, it says "If at least one of the routes to be
aggregated has ATOMIC_AGGREGATE path attribute, then the aggregated route SHALL
have this attribute as well."  My question is, wouldn't all the routes have to
have the ATOMIC_AGGREGATE attribute in order for aggregation to take place based
on the initial quote?  The way the second quote's worded, it sounds like that
wouldn't necessarily have to be the case.  Thanks.

Eric

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---

From: Michael Dell <[email-masked]>
Date: Fri, 2 Jul 2004 16:46:11 +0100

Hi Eric

The first quote, from section 9.2.2.2, is saying that you can only aggregate
together attributes of the same type.  This is pretty obvious, and just
means you can't try to aggregate next-hop information (type code 3) with
local_pref information (type code 5).  

The second quote requires that the atomic aggregate attribute is not lost
during the aggregation.  Technically, if 1 route has the atomic aggregate
attribute, and another does not, then you are not aggregating two attributes
of different type codes, you are merely aggregating an attribute with
nothing, and ending up with the original attribute.  

Regards

Mike Dell
Networking Protocols Group
Data Connection Ltd
Tel: +44 20 8366 1177
Fax: +44 20 8367 8501
E-mail: [email-masked]
Web: http://www.dataconnection.com

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Eric P. Barrett
Sent: 02 July 2004 15:03
To: [email-masked]
Subject: [Idr] Aggregation Question

Hi,

According to draft 24, "Path attributes that have different type codes can
not
be aggregated together."  Later, it says "If at least one of the routes to
be
aggregated has ATOMIC_AGGREGATE path attribute, then the aggregated route
SHALL
have this attribute as well."  My question is, wouldn't all the routes have
to
have the ATOMIC_AGGREGATE attribute in order for aggregation to take place
based
on the initial quote?  The way the second quote's worded, it sounds like
that
wouldn't necessarily have to be the case.  Thanks.

Eric