Robust Header Compression (rohc)

NOTE: This charter is a snapshot of the . It may now be out-of-date.

Last Modified: 2007-09-28

Chair(s):

Carl Knutsson <carl.knutsson@effnet.com>

Transport Area Director(s):

Magnus Westerlund <magnus.westerlund@ericsson.com>
Lars Eggert <lars.eggert@nokia.com>

Transport Area Advisor:

Magnus Westerlund <magnus.westerlund@ericsson.com>

Technical Advisor(s):

Erik Nordmark <erik.nordmark@sun.com>
Carsten Bormann <cabo@tzi.org>

Mailing Lists:

General Discussion: rohc@ietf.org
To Subscribe: rohc-request@ietf.org
Archive: http://www.ietf.org/mail-archive/web/rohc/index.html

Description of Working Group:

The Robust Header Compression (ROHC) Working Group was formed to
develop new header compression protocols, designed to suit today's and
future target link technologies. Most specifically, the ROHC protocols
were to take into account typical needs presented by various wireless
link technologies, and perform well for cellular links built using
technologies such as WCDMA, EDGE, and CDMA-2000. Protocol development
has thus focused on coping with issues such as high loss rates and long
round trip times. 

The WG has specified a common compression protocol platform, the ROHC
framework, along with a number of compression protocols (profiles).
Most focus has been on compression of the Real-time Transport Protocol
(RTP) headers, but profiles have also been specified for compression of
UDP, ESP, IP-only, UDP-Lite, and TCP headers. The WG has further
produced a ROHC link integration specification for PPP, an optimized
RTP compression scheme for "0-byte compression", a ROHC MIB, as well as
various informational documents related to ROHC header compression
and/or header compression in general. 

In addition to the work on header compression, the ROHC WG has also
developed the SigComp (Signaling Compression) protocol for end-to-end
compression of text-based signaling protocol messages. 

The working group maintains connections with other standardization
organizations developing cellular technology for IP, such as 3GPP and
3GPP-2, to ensure that its output fulfills their requirements and will
be put to good use. 

The current aims of the working group are: 

- to carry out a re-work of the ROHC framework and profiles 
specifications, hereafter referred to as the ROHCv2 project. The
purpose of the ROHCv2 project is to generate a separate framework
specification, not changing the framework part of the ROHC protocol, as
well as a set of revised compression profiles. The most specific goals
with the ROHCv2 profiles are to improve tolerance to packet reordering
between compressor and decompressor, and to reduce the overall
complexity of the protocol. It should be noted that the v2 profiles
will thus not be compatible with the original (ROHCv1) profiles, which
means less complex ROHC implementations can be realized by not
providing support for ROHCv1 (over links not yet supporting ROHC, or by
shifting out support for ROHCv1 in the long run). Profile support is
agreed through the ROHC channel negotiation, which is part of the ROHC
framework and thus not changed by ROHCv2. 

- to update and correct the original profile specifications through
publication of the "Corrections and Clarifications to RFC 3095"- 
document. 

- to finalize the ROHC profile work for TCP header compression. 

- to develop and/or document proper protocol solutions to apply ROHC
over IPsec tunnels. 

- to finalize the "SigComp implementer's guide" and "SigComp for SIP"
documents. 

The longer term goal of the working group is to advance all its
specifications to Draft Standard status (with an exception for the
original profiles being revised as part of the ROHCv2 activity).

Goals and Milestones:

Done  Submit I-D on Requirements for IP/UDP/RTP header compression.
Done  Submit I-D of layer-2 design guidelines.
Done  Submit I-D(s) proposing IP/UDP/RTP header compression schemes.
Done  Submit I-D of Requirements for IP/TCP header compression.
Done  Requirements for IP/UDP/RTP header compression submitted to IESG for publication as Informational.
Done  Resolve possibly multiple IP/UDP/RTP compression schemes into a single scheme.
Done  Submit I-D on IP/TCP header compression scheme.
Done  IP/UDP/RTP header compression scheme submitted to IESG for publication as Proposed Standard.
Done  Layer-2 design guidelines submitted to IESG for publication as Informational.
Done  Initial draft on general signaling compression security analysis.
Done  Requirements and assumptions for signaling compression
Done  Signaling compression scheme submitted to IESG for publication as Proposed Standard, including security approach for SIP compression usage.
Done  General signaling compression security analysis submitted to IESG for publication as Informational.
Done  ROHC MIB submitted to IESG for publication as Proposed Standard.
Done  ROHC IP-only profile submitted to IESG for publication as Proposed Standard
Done  ROHC UDP Lite schemes submitted to IESG for publication as Proposed Standard.
Done  Requirements for IP/TCP header compression submitted to IESG for publication as Informational.
Done  Problem analysis ROHC-over-channels-that-can-reorder-packets submitted to IESG for publication as Informational
Done  I-Ds of ROHC IP/UDP/RTP bis, framework and profiles separated.
Done  RFC 3095 Implementer's Guide submitted to IESG for publication as Proposed Standard
Done  IP/TCP compression scheme submitted to IESG for publication as Proposed Standard
Done  ROHC framework submitted to IESG for publication as Proposed Standard
Done  SigComp for SIP submitted to IESG for publication as Proposed Standard
Dec 2006  Revised ROHC IP/UDP/RTP profiles submitted to IESG for publication as Proposed Standard
Done  SigComp Implementer's Guide submitted to IESG for publication as Proposed Standard
Jan 2007  RObust Header Compression Protocol Number Registration submitted to IESG for publication as Proposed Standard
Feb 2007  ROHC encapsulation profile(s) for IPHC/CRTP/eCRTP submitted to IESG for publication as Proposed Standard
Mar 2007  IKE/IPsec extensions for HC-session Parameter Negotiation submitted to IESG for publication as Proposed Standard
Mar 2007  Header Compression over IPsec (HCoIPsec) submitted to IESG for publication as Informational
Jun 2007  Recharter of WG to develop additional profiles if needed, or possible additional compression schemes. Consideration of concluding the working group.

Internet-Drafts:

  • draft-ietf-rohc-hcoipsec-12.txt
  • draft-ietf-rohc-ikev2-extensions-hcoipsec-10.txt
  • draft-ietf-rohc-ipsec-extensions-hcoipsec-06.txt
  • draft-ietf-rohc-rfc4995bis-03.txt

    Request For Comments:

    RFCStatusTitle
    RFC3095 PS RObust Header Compression (ROHC)
    RFC3096 I Requirements for robust IP/UDP/RTP header compression
    RFC3241 PS ROHC over PPP
    RFC3242 PS A Link-Layer Assisted ROHC Profile for IP/UDP/RTP
    RFC3243 I Requirements and assumptions for ROHC 0-byte IP/UDP/RTP compression
    RFC3320 PS Signaling Compression
    RFC3321 I SigComp - Extended Operations
    RFC3322 I Signaling Compression Requirements & Assumptions
    RFC3408 PS Zero-byte Support for Reliable Bidirectional Mode (R-mode) in Extended Link-Layer Assisted RObust Header Compression (ROHC) Profile
    RFC3409 I Lower Layer Guidelines for Robust RTP/UDP/IP Header Compression
    RFC3759 I RObust Header Compression (ROHC):Terminology and Channel Mapping Examples
    RFC3816 Standard Definitions of Managed Objects for Robus Header Compression
    RFC3843 Standard RObust Header Compression (ROHC): A Compression Profile for IP
    RFC4019 Standard RObust Header Compression (ROHC):Profiles for UDP-Lite
    RFC4077 Standard A Negative Acknowledgement Mechanism for Signaling Compression
    RFC4163 I RObust Header Compression (ROHC): Requirements on TCP/IP Header Compression
    RFC4164 Standard RObust Header Compression (ROHC):Context Replication for ROHC Profiles
    RFC4224 I RObust Header Compression (ROHC): ROHC over Channels that can Reorder Packets
    RFC4362 Standard RObust Header Compression (ROHC): A Link-Layer Assisted Profile for IP/UDP/RTP
    RFC4413 I TCP/IP Field Behavior
    RFC4464 I Signaling Compression (SigComp) Users' Guide
    RFC4465 I Signaling Compression (SigComp) Torture Tests
    RFC4815 PS RObust Header Compression (ROHC): Corrections and Clarifications to RFC 3095
    RFC4896 PS Signaling Compression (SigComp) Corrections and Clarifications
    RFC4995 PS The RObust Header Compression (ROHC) Framework
    RFC4996 PS RObust Header Compression (ROHC): A Profile for TCP/IP (ROHC-TCP)
    RFC4997 PS Formal Notation for RObust Header Compression (ROHC-FN)
    RFC5049 PS Applying Signaling Compression (SigComp) to the Session Initiation Protocol (SIP)
    RFC5225 PS RObust Header Compression Version 2 (ROHCv2): Profiles for RTP, UDP, IP, ESP and UDP Lite