Subject: Hierarchically-encoded traffic and Int-Serv

From: Luca Salgarelli <[email-masked]>
Date: Wed, 11 Jun 1997 14:38:48 +0200

Dear People@Int-Serv,

I would like to rise an issue about the support offered by the Int-Serv
architecture to hierarchically-encoded flows (traffic flows coded so as
to have a base-layer plus a number of enhancement-layers).

If I have correctly understood, current approach for handling
Int-Serv-related issues with hierarchically-encoded traffic is to send
each hierarchic-level to a different UDP-port/IP Mcast address. In this
way it is necessary to use a separate RSVP session for each
hierarchic-level, without exploiting the "heterogeneity accommodation"
features of RSVP. 

I would like to propose a new simple approach for handling
hierarchic-traffic within the Int-Serv architecture. The idea is simply
to add to the int-serv characterization parameters a new parameter,
which describes the entire hierarchic-traffic and each of its
sub-levels. In this way it should be possible to use one single RSVP
session for each hierarchically-encoded flow (i.e., a single RSVP
session for the whole set of sub-streams).

Such new parameter should contain both the traffic description of each
sub-level, plus  an object used for the discrimination of the packets
belonging to each sub-level.

What do you think about this kind of approach?

Best regards
Luca
_________________
 Luca Salgarelli
 CEFRIEL / Politecnico di Milano, Via Cozzi 53, I-20126 Milano (Italy)
 tel: +39-2-66.161.257    or    +39-2-66.161.1
 fax: +39-2-66.100.448
 e-mail: [email-masked]

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From: Craig Partridge <[email-masked]>
Date: Wed, 11 Jun 97 15:13:56 -0700

My experience in this area is that it is hard to evaluate concepts unless
they're reduced to a protocol proposal.  So I'd suggest a proposal.

Keep in mind that there's a strong chance that the data contents of the
UDP/TCP/IP datagram will be encrypted.  That may make finding a good
discriminator hard.

Craig