Adaptive Header ComprEssion (ACE) for Real-Time Multimedia

Document Type Replaced Internet-Draft (rohc WG)
Last updated 2000-05-25
Replaced by RFC 3095
Stream IETF
Intended RFC status (None)
Expired & archived
pdf htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Replaced by draft-ietf-rohc-rtp
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


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.


Christopher Clanton (
Haihong Zheng (
Khiem Le (
Zhigang Liu (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)