Robust Header Compression (rohc)
--------------------------------

 Charter
 Last Modified: 2007-09-28

 Current Status: Active Working Group

 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:

Posted Revised         I-D Title   <Filename>
------ ------- --------------------------------------------
Nov 2005 Dec 2009   <draft-ietf-rohc-hcoipsec-12.txt>
                Integration of Robust Header Compression (ROHC) over IPsec 
                Security Associations 

Sep 2006 Dec 2009   <draft-ietf-rohc-ikev2-extensions-hcoipsec-10.txt>
                IKEv2 Extensions to Support Robust Header Compression over 
                IPsec (ROHCoIPsec) 

Aug 2007 Dec 2009   <draft-ietf-rohc-ipsec-extensions-hcoipsec-06.txt>
                IPsec Extensions to Support Robust Header Compression over 
                IPsec (ROHCoIPsec) 

Aug 2008 Jan 2010   <draft-ietf-rohc-rfc4995bis-03.txt>
                The RObust Header Compression (ROHC) Framework 

 Request For Comments:

  RFC   Stat Published     Title
------- -- ----------- ------------------------------------
RFC3095 PS   Jul 2001    RObust Header Compression (ROHC) 

RFC3096 I    Jul 2001    Requirements for robust IP/UDP/RTP header compression 

RFC3242 PS   May 2002    A Link-Layer Assisted ROHC Profile for IP/UDP/RTP 

RFC3243 I    May 2002    Requirements and assumptions for ROHC 0-byte IP/UDP/RTP 
                       compression 

RFC3241 PS   May 2002    ROHC over PPP 

RFC3408 PS   Dec 2002    Zero-byte Support for Reliable Bidirectional Mode 
                       (R-mode) in Extended Link-Layer Assisted RObust Header 
                       Compression (ROHC) Profile 

RFC3409 I    Dec 2002    Lower Layer Guidelines for Robust RTP/UDP/IP Header 
                       Compression 

RFC3321 I    Jan 2003    SigComp - Extended Operations 

RFC3320 PS   Jan 2003    Signaling Compression 

RFC3322 I    Jan 2003    Signaling Compression Requirements & Assumptions 

RFC3759 I    Apr 2004    RObust Header Compression (ROHC):Terminology and Channel 
                       Mapping Examples 

RFC3816Standard  Jun 2004    Definitions of Managed Objects for Robus Header 
                       Compression 

RFC3843Standard  Jul 2004    RObust Header Compression (ROHC): A Compression Profile 
                       for IP 

RFC4019Standard  Apr 2005    RObust Header Compression (ROHC):Profiles for UDP-Lite 

RFC4077Standard  May 2005    A Negative Acknowledgement Mechanism for Signaling 
                       Compression 

RFC4163 I    Aug 2005    RObust Header Compression (ROHC): Requirements on TCP/IP 
                       Header Compression 

RFC4164Standard  Sep 2005    RObust Header Compression (ROHC):Context Replication for 
                       ROHC Profiles 

RFC4224 I    Jan 2006    RObust Header Compression (ROHC): ROHC over Channels 
                       that can Reorder Packets 

RFC4362Standard  Jan 2006    RObust Header Compression (ROHC): A Link-Layer Assisted 
                       Profile for IP/UDP/RTP 

RFC4413 I    Mar 2006    TCP/IP Field Behavior 

RFC4464 I    May 2006    Signaling Compression (SigComp) Users' Guide 

RFC4465 I    Jun 2006    Signaling Compression (SigComp) Torture Tests 

RFC4815 PS   Feb 2007    RObust Header Compression (ROHC): Corrections and 
                       Clarifications to RFC 3095 

RFC4896 PS   Jun 2007    Signaling Compression (SigComp) Corrections and 
                       Clarifications 

RFC4997 PS   Jul 2007    Formal Notation for RObust Header Compression (ROHC-FN) 

RFC4996 PS   Jul 2007    RObust Header Compression (ROHC): A Profile for TCP/IP 
                       (ROHC-TCP) 

RFC4995 PS   Jul 2007    The RObust Header Compression (ROHC) Framework 

RFC5049 PS   Dec 2007    Applying Signaling Compression (SigComp) to the Session 
                       Initiation Protocol (SIP) 

RFC5225 PS   Apr 2008    RObust Header Compression Version 2 (ROHCv2): Profiles 
                       for RTP, UDP, IP, ESP and UDP Lite