The MPLS WG Archive

["St. Amour, Kevin" <Kevin.StAmour@teleglobe.com>]

Kevin St.Amour
Teleglobe International
> 3900 Skyhawk Drive
> Chantilly, Virginia 20151
* IP Provisioning Engineer
*  703-871-7560
*kstamour@teleglobe.com
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> -----Original Message-----
> From: Eric Gray [mailto:eric.gray@sandburst.com]
> Sent: Friday, July 27, 2001 2:35 PM
> To: Fabris Sergio
> Cc: mpls@UU.NET
> Subject: Re: Ordered aggregate
> 
> 
> Sergio,
> 
>     Please see below.  BA='Behavior Aggregate', OA='Ordered 
> Aggregate'.
> 
> You wrote:
> 
> > what is the meaning for ORDERER AGGREGATE ?
> 
> That's when you have a group of people arriving at a fast 
> food restaurant
> all at the same time. :-)


So... Is BA='Behavior Aggregate'  when people request separate checks at one
table in a sit down restaurant?




> 
> An 'ordered aggregate' is defined in "MPLS Support of 
> Differentiated Services"
> (at 
> http://www.ietf.org/internet-drafts/draft-ietf-mpls-diff-ext-0
9.txt), as
"The set of Behavior Aggregates which share an ordering constraint" where
a Behavior Aggregate is a set of "IP packets crossing a link and requiring
the
same Diff-Serv behavior".

Sharing an ordering constraint seems to mean that the packets with in an OA
need to depart in the same order as they arrive.

An often used example of an OA is an AF Class - where different packets in
the same AF class get the same service, except that they may have different
drop precendents.  In this example, packets that are not dropped, should be
in
the same order when they depart as the order in which they arrived.


>
> I read that E-LSP allows multiple ordered aggregates.  Then I read that an
> E-LSP support eight BAs (behavior aggregates).
>
> Does OA have a relation with BA??

See above.

>
>
> Thank.
>
> Sergio