Subject: I-D ACTION:draft-ietf-rohc-rtp-ace-00.txt

From: [email-masked]
Date: Fri, 26 May 2000 08:54:40 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Robust Header Compression Working Group of the IETF.

	Title		: Adaptive Header ComprEssion (ACE) for Real-Time 
                          Multimedia
	Author(s)	: K. Le, C. Clanton, Z. Liu, H. Zheng
	Filename	: draft-ietf-rohc-rtp-ace-00.txt
	Pages		: 50
	Date		: 25-May-00
	
When Real-Time Multimedia over IP is applied to cellular systems, it
is critical to minimize the overhead of the IP/UDP/RTP header, as
spectral efficiency is a top requirement.  Robustness to errors and
error bursts is also a must.
Existing IP/UDP/RTP header compression schemes such as that presented
in IETF RFC 2508 [CRTP], do not provide sufficient performance in
such environments.  This report describes a new scheme (ACE, or
Adaptive header ComprEssion) , which like RFC 2508, is based on the
idea that most of the time IP/UDP/RTP fields are either constant or
can be extrapolated in a linear fashion.  However, ACE incorporates
several additional concepts which enable it to provide excellent
compression efficiency (exceeds the performance of [CRTP]) along with
a high degree of error-resiliency.  Some of the concepts employed,
such as Variable Length Encoding (VLE), enable ACE to adapt to
changing behavior in the IP/UDP/RTP header fields, such that good
efficiency and robustness characteristics are maintained over a wide
range of operating conditions.
ACE is a general framework that can be parameterized to account for
the existence/non-existence and performance characteristics of the
feedback channel.  Thus, ACE is applicable over both bi-directional
and unidirectional links.
ACE is also able to perform a seamless handoff, i.e. the scheme can
resume efficient compression operation immediately after handoff.

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