Subject: [rohc] ROHC-TCP proposal: add a generation identifier to IR and IR-CR packets.

From: "Ghyslain Pelletier (LU/EAB)" <[email-masked]>
Date: Mon, 10 Oct 2005 16:49:57 +0200

Hi RoHCers,

Kristofer and myself would like to propose adding a generation identifier to the IR and IR-CR packet formats, to identify a version of a context associated with a CID.

A change in the GenID carried without an IR/IR-CR packet from its value in the context for the CID for which the packet is sent would basically signal the decompressor that it can flush the entire context and start anew. In other words, it gives the possibility to the compressor and the decompressor to differentiate between a context refresh and a context (re)initialization, in either unidirectional or bidirectional operation. The cost would be one additional octet in the IR/IR-CR packet.

This would be useful in order to solve the issue of the CID-reuse ambiguity within the same profile, as described in the implementer's guide in section 7.2:
http://www.ietf.org/internet-drafts/draft-ietf-rohc-rtp-impl-guide-15 .txt

If we all agree and I don't hear any objections, I will propose new text to add to the ROHC-TCP draft soon.

/Ghyslain

--
 Ghyslain Pelletier, Dipl. Ing.
 Wireless IP Optimizations
 Ericsson Research, Corporate Unit

 Ericsson AB, Laboratoriegränd 11
 Box 920, S-97128 Luleå, SWEDEN
 Phone : +46 (0)  8 404 29 43
 Mobile: +46 (0) 70 264 83 14
 Ghyslain.Pelletier at ericsson.com
 http://www.ericsson.com

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From: "Lars-Erik Jonsson" <[email-masked]>
Date: Mon, 10 Oct 2005 17:33:35 +0200

Ghyslain,

Please explain why this would be a problem for the TCP profile, the 
reference you gave only talks about this as a problem with multi-mode 
profiles, while the TCP profile does not have that RFC3095-problem.

/L-E

----- Original Message ----- 
From: "Ghyslain Pelletier (LU/EAB)" <[email-masked]>
To: <[email-masked]>
Sent: Monday, October 10, 2005 4:49 PM
Subject: [rohc] ROHC-TCP proposal: add a generation identifier to IR 
andIR-CR packets.

Hi RoHCers,

Kristofer and myself would like to propose adding a generation identifier to 
the IR and IR-CR packet formats, to identify a version of a context 
associated with a CID.

A change in the GenID carried without an IR/IR-CR packet from its value in 
the context for the CID for which the packet is sent would basically signal 
the decompressor that it can flush the entire context and start anew. In 
other words, it gives the possibility to the compressor and the decompressor 
to differentiate between a context refresh and a context (re)initialization, 
in either unidirectional or bidirectional operation. The cost would be one 
additional octet in the IR/IR-CR packet.

This would be useful in order to solve the issue of the CID-reuse ambiguity 
within the same profile, as described in the implementer's guide in section 
7.2:
http://www.ietf.org/internet-drafts/draft-ietf-rohc-rtp-impl-guide-15 .txt

If we all agree and I don't hear any objections, I will propose new text to 
add to the ROHC-TCP draft soon.

/Ghyslain