SIPPING Haseeb Akhtar Internet Draft Mohamed Khalil Expires: August 26, 2006 Dave Brombal Anthony Jones Nortel February 27, 2006 3G Wireless Support in the SIP/SDP Static Dictionary for Signaling Compression (SigComp) draft-akhtar-sipping-3g-static-dictionary-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 26, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract While using SIGComp [4] based compression in SIP/SDP [5] [6], it is imperative to have access to a static dictionary to be used on the first SIP message that the compressor sends out. The session set up time can be reduced significantly if the compression rate of the first SIP message is considerably high. Akhtar, et al. Expires August 26, 2006 [Page 1] Internet-Draft 3G Static Dictionary February 2006 The existing static dictionary for SIP and SDP [2], however, does not include some wireless specific data elements. This document introduces these new data elements that are specific to various wireless access technologies. These new data elements are part of the first SIP message (i.e., originating SIP Invite) used to initiate a session. Akhtar, et al. Expires August 26, 2006 [Page 2] Internet-Draft 3G Static Dictionary February 2006 Table of Contents 1. Introduction............................................... 3 2. Design considerations...................................... 3 3. 3G Data Elements........................................... 4 4. Binary representation of the 3G dictionary................. 4 5. Security Considerations.................................... 5 6. IANA Considerations........................................ 5 7. Acknowledgements........................................... 5 8. References................................................. 5 8.1 Normative References................................... 5 8.2 Informative References................................. 6 Authors' Addresses............................................ 6 Intellectual Property and Copyright Statements ............... 7 1. Introduction While using SIGComp [3] based compression in SIP/SDP [5] [6], it is imperative to have access to a static dictionary to be used on the first SIP message that the compressor sends out. The session set up time can be reduced significantly if the compression rate of the first SIP message is considerably high. The existing static dictionary for SIP and SDP [2], however, does not include some wireless specific data elements. This document introduces these new data elements that are specific to various wireless access technologies. These new data elements are part of the first SIP message (i.e., originating SIP Invite) used to initiate a session. 2. Design considerations The static 3G SIP/SDP dictionary is a collection of well-known strings related to 3rd generation wireless access technologies that appear in most of the SIP and SDP messages. The new data elements should be inclusive of the existing SIP/SDP static data dictionary specified by [2]. Akhtar, et al. Expires August 26, 2006 [Page 3] Internet-Draft 3G Static Dictionary February 2006 3. 3G Data Elements The following SIP data elements have been introduced by this proposal. - 'P-Preferred-Identity' - 'P-Access-Network-Info' - 'Require: sec-agree, precondition' - 'Max-Forwards: 70' - 'Supported: 100 rel' - 'Spi:s' - 'Port:c=' - 'Port:s=' The following SDP data elements have been introduced by this proposal. - 'Content-Type: application/SDP' - 'a=des:qos mandatory, local sendrecv' - 'a=des:qos none, local sendrecv' - 'a=inactive' 4. Binary representation of the 3G dictionary This section lists the SIP and SDP input strings used in generating the dictionary, as well as a priority value, the offset of the string in the generated dictionary, the length of the string, and one or more references into the referenced documents that motivate the presence of this string. Note that the notation "[CRLF]" stands for a sequence of two bytes with the values 0x0d and 0x0a, respectively. The priority value is used for determining the position of the string in the dictionary. Lower priority values (higher priorities) cause the string to occur at a later position in the dictionary, making it more efficient to reference the string in certain compression algorithms. Hence, lower priority values were assigned to strings more likely to occur. Akhtar, et al. Expires August 26, 2006 [Page 4] Internet-Draft 3G Static Dictionary February 2006 The following the list of strings with their associated priority, offset, length and reference sections. Offset Reference ------ --------- String Priority Length ------ -------- ------ "[CRLF]Max-Forwards: 70" 1 TBD 11 [3] 7.2.3.1 "[CRLF]P-Preferred-Identity" 1 TBD 16 [3] 7.2.3.1 "[CRLF]P-Access-Network-Info" 1 TBD 17 [3] 7.2.3.1 "[CRLF]Require: sec-agree, precondition" 1 TBD 22 [3] 7.2.3.1 "[CRLF]Supported: 100 rel" 1 TBD 14 [3] 7.2.3.1 "[CRLF]Spi:s" 1 TBD 7 [3] 7.2.3.1 "[CRLF]Port:c=" 1 TBD 9 [3] 7.2.3.1 "[CRLF]Port:s=" 1 TBD 9 [3] 7.2.3.1 "[CRLF]Content-Type: application/SDP" 1 TBD 1F [3] 7.2.3.1 "[CRLF]a=des:qos mandatory, local sendrecv" 1 TBD 25 [3] 7.2.3.1 "[CRLF]a=des:qos none, remote sendrecv" 1 TBD 21 [3] 7.2.3.1 "[CRLF]a=inactive" 1 TBD C [3] 7.2.3.1 5. Security Considerations The security considerations of [2] apply. This proposal does not introduce any known additional security risk. 6. IANA Considerations None. 7. Acknowledgements 8. References 8.1 Normative References [1] Bradner, S., "Key words for use in RFCs to indicate requirement levels", BCP 14, RFC 2119, March 1997. [2] Garcia-Martin, M., Borman, C., Ott, J., Price, R. and A. B. Roach, "The Session Initiation Protocol (SIP) and Session Description Protocol(SDP) Static Dictionary for Signaling Compression (SigComp)", RFC 3485, February 2003. Akhtar, et al. Expires August 26, 2006 [Page 5] Internet-Draft 3G Static Dictionary February 2006 [3] "Signaling Flows for the IP Multimedia Call Control based on Session Initiated Protocol (SIP) and Session Description Protocol (SDP)", 3GPP TS 24.228 v5.14.0, December 2005. 8.2 Informative References [4] Price, R., Bormann, C., Christoffersson, J., Hannu, H., Liu, Z. and J. Rosenberg, "Signaling Compression (SigComp)", RFC 3320, January 2003. [5] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [6] Handley, M., Jacobson, V. and C. Perkins, "SDP: Session Description Protocol", RFC 2327, April 1998. [7] Garcia-Martin, M., "3rd-Generation Partnership Project (3GPP) Release 5 requirements on the Session Initiation Protocol (SIP)", Work in Progress. Authors' Addresses Haseeb Akhtar Nortel 2221 Lakeside Blvd Richardson, TX 75082 US Email: haseebak@nortel.com Mohamed Khalil Nortel Networks 2221 Lakeside Blvd Richardson, TX 75082 US Email: mkhalil@nortel.com Dave Brombal Nortel 2221 Lakeside Blvd Richardson, TX 75082 US Email: davidb@nortel.com Akhtar, et al. Expires August 26, 2006 [Page 6] Internet-Draft 3G Static Dictionary February 2006 Anthony Jones Nortel 3500 Carling Avenue Ottawa, Ontario K2H 8E9 Canada Email: ajones@nortel.com Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Akhtar, et al. Expires August 26, 2006 [Page 7] Internet-Draft 3G Static Dictionary February 2006 Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society.