Subject: Protocol Action: A Link-Layer Assisted ROHC Profile for IP/UDP/RTP to Proposed Standard

From: The IESG <[email-masked]>
Date: Wed, 30 Jan 2002 10:09:50 -0500

The IESG has approved the Internet-Draft 'A Link-Layer Assisted ROHC
Profile for IP/UDP/RTP' <draft-ietf-rohc-rtp-lla-03.txt> as a Proposed
Standard.

In the same action, the IESG approved publication of Requirements and
assumptions for ROHC 0-byte IP/UDP/RTP compression
<draft-ietf-rohc-rtp-0-byte-requirements-02.txt> as an Informational
RFC.

These documents are the product of the Robust Header Compression
Working Group.  The IESG contact persons are Allison Mankin and Scott
Bradner.

Technical Summary

     This document set defines a ROHC profile for compression of IP/UDP/RTP
      packets that leverages functionality provided by the lower layers
      by completely eliminating the header for most packets during
      optimal operation. The requirements on the enabling lower layer
      functionality are discussed by the 0-byte requirements document.
      The motivation is not super-optimization (squeezing out that last
      octet) but the adaptation of the RFC 3095 profile to existing, older
      air interfaces (such as those based on GSM) in which the single octet
      ROHC header pushes a packet voice stream into the next higher fixed
      packet size of the link. The ROHC RTP profile (RFC 3095) allows
      more flexible air interfaces to attain excellent spectrum efficiency
      with RTP media, and this profile extends that result to a larger
      set of deployed environments.

Working Group Summary
 
      There was initially working group dissent about the goal of
      a 0-byte header compression, but the work settled into
      showing compatibility with RFC 3095 and applicability to
      significant air-interfaces and traffic usages on them (the
      profile is expected to see use on GPRS and CDMA2000).
      Experimental implementations were reported on during the
      development of the draft, from both Nokia and Ericsson.
      Results of both experiment and discussion led to providing
      only Unidirectional and Optimistic bidirectional types of
      RFC 3095 in this spec (U-mode and O-mode) and for the
      support for Reliable bidirectional (R-mode) to be separated
      into its own draft.
 
Protocol Quality
 
      Allison Mankin reviewed the documents for the IESG.
      Coding and testing were reported throughout the
      draft development, and there was extensive working group
      review of the applicability as well as the protocol.