Network Working Group K. Drage Internet-Draft Lucent Technologies Expires: April 20, 2006 October 17, 2005 Update to RFC 3455: (Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3rd-Generation Partnership Project (3GPP) draft-drage-sipping-rfc3455bis-00 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 April 20, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract RFC3455 [3] describes a set of private Session Initiation Protocol (SIP) headers (P-headers) used by the 3rd-Generation Partnership Project (3GPP), along with their applicability, which is limited to particular environments. Since RFC3455 [3] was approved in 2003, a number of minor corrections and extensions have arisen whose documentation would be convenient to 3GPP. This proposed update to RFC3455 [3] provides those minor corrections and extensions. Drage Expires April 20, 2006 [Page 1]
Internet-Draft Update to RFC 3455 October 2005 1. Overall applicability While this document updates RFC3455 [3], it makes no changes to the overall applicability. Drage Expires April 20, 2006 [Page 2]
Internet-Draft Update to RFC 3455 October 2005 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, RFC2119 [1]. Drage Expires April 20, 2006 [Page 3]
Internet-Draft Update to RFC 3455 October 2005 3. Overview This document proposes a number of additions to RFC3455 [3] such as: further clarification on proxy procedures for the P-Associated-URI header. further clarification on the relationship between the History-Info header and the P-Called-Party-ID header. clarification on the UA procedures for the P-Charging-Vector and P-Charging-Function-Addresses header. definition of additional values of access technology in the P-Access-Network-Info header. clarification that additional parameters can be defined elsewhere for the P-Charging-Vector header. Drage Expires April 20, 2006 [Page 4]
Internet-Draft Update to RFC 3455 October 2005 4. Issues 4.1. Procedures for the P-Associated-URI header at a proxy RFC3455 [3] indicates that it defines no procedures for the P-Associated-URI header at a proxy. What is implicitly meant here is that the proxy does not add, read, modify or delete the header, and therefore RFC3261 [2] proxy procedures only apply to the header. 4.2. P-Called-Party-ID header and the History-Info header At the time RFC3455 [3] was drafted, the History-Info header was a long way from specification; this header has now been specified and approved in draft-ietf-sip-history-info-06 [4]. It is acknowledged that the History-Info header will provide equivalent coverage to that of the P-Called-Party-ID header. However the P-Called-Party-ID header is used entirely within the 3GPP system and does not appear to SIP entities outside that of a single 3GPP operator. Additionally the P-Called-Party-ID header has been defined within 3GPP systems since release 5, and therefore it is realistic to expect implementations to be already released to the field. It is therefore considered that replacement of the P-Called-Party-ID header within 3GPP systems causes more issues that it solves, and therefore the update of RFC3455 [3] to remove the P-Called-Party-ID header will not be addressed. However it is recommended that any new usage of this type of functionality should use the History-Info header rather than the P-Called-Party-ID header. 4.3. Procedures at the UA for the P-Charging-Function Addresses header The text in section 4.5.2.1 of RFC3455 [3] does not adequately take into account procedures for UAs located inside the private network, e.g. as gateways and suchlike which may play a full part in network charging procedures. Section 4.5.2.1 is replaced with the following text: This document does not specify any procedure at a UA located outside the administrative domain of a private network, with regard to the P-Charging-Function-Addresses header. Such UAs need not understand this header. Drage Expires April 20, 2006 [Page 5]
Internet-Draft Update to RFC 3455 October 2005 However, it might be possible that a UA is located within the administrative domain of a private network (e.g., a PSTN gateway, or conference mixer), and it may have access to the addresses of the charging entities. In this cases, a UA MAY insert the P-Charging-Function-Addresses header in a SIP request or response when the next hop for the message is a proxy or UA located in the same administrative domain. Similar such a UA may use the contents of the P-Charging-Function-Addresses header in communicating with the charging entities. 4.4. Procedures at the UA for the P-Charging-Vector header The text in section 4.6.2.1 of RFC3455 [3] does not adequately take into account procedures for UAs located inside the private network, e.g. as gateways and suchlike which may play a full part in network charging procedures. Section 4.6.2.1 is replaced with the following text: This document does not specify any procedure at a UA located outside the admininstrative domain of a private network, with regard to the P-Charging-Vector header. UAs need not understand this header. However, it might be possible that a UA is located within the administrative domain of a private network (e.g., a PSTN gateway, or conference mixer), and it may it may interact with the charging entities. In this cases, a UA MAY insert the P-Charging-Vector header in a SIP request or response when the next hop for the message is a proxy or UA located in the same administrative domain. Similar such a UA may use the contents of the P-Charging- Voector header in communicating with the charging entities. 4.5. Recognition of additional values of access technology in the P-Access-Network-Info header A number of new access technologies are contemplated in 3GPP, and the reuse of IMS to support Next Generation Networks (NGN) is also resulting in new access technologies. Values for access technologies are defined explicitly in RFC3455 [3] and no IANA procedures are defined to maintain a separate registry. Input is sought on whether the appropriate extension mechanism for the P-Access-Network-Info header is to create an IANA registry. In the meanwhile, the proposed modification to the syntax is given below. It is therefore proposed that section 5.4 of RFC3455 [3] is enhanced as follows: Drage Expires April 20, 2006 [Page 6]
Internet-Draft Update to RFC 3455 October 2005 The syntax of the P-Access-Network-Info header is described as follows: P-Access-Network-Info = "P-Access-Network-Info" HCOLON access-net- spec access-net-spec = access-type *(SEMI access-info) access-type = "IEEE-802.11a" / "IEEE-802.11b" / "IEEE-802.11e" / "IEEE-802.11g" / "3GPP-GERAN" / "3GPP-UTRAN-FDD" / "3GPP-UTRAN- TDD" / "3GPP-CDMA2000" / token access-info = cgi-3gpp / utran-cell-id-3gpp / extension-access- info extension-access-info = gen-value cgi-3gpp = "cgi-3gpp" EQUAL (token / quoted-string) utran-cell-id-3gpp = "utran-cell-id-3gpp" EQUAL (token / quoted- string) The access-info may contain additional information relating to the access network. The values for "cgi-3gpp" and "utran-cell-id- 3gpp" are defined in 3GPP TS 24.229 [15]. There are ongoing discussions within 3GPP that may result in additional values being added to this section, e.g. XDSL and WiMax, and there may also be associated parameters to add. It appears additional values have also been defined by 3GPP2, and there is ongoing discussions within 3GPP2 that may result in further additional values being added to this section, and there may also be associated parameters to add. 4.6. Definition of additional parameters to the P-Charging-Vector header Section 5.6 of RFC3455 [3] defines the syntax of the P-Charging- Vector header. Additional parameters were considered too application specific for specification in RFC3455 [3], but it was acknowledged that they would exist, and indeed additional specification of such parameters, relating to specific access technologies, has occurred in 3GPP. This update therefore defines that applications using the P-Charging- Vector header within their own applicability are allowed to define Drage Expires April 20, 2006 [Page 7]
Internet-Draft Update to RFC 3455 October 2005 generic-param extensions without further reference to the IETF specification process. Drage Expires April 20, 2006 [Page 8]
Internet-Draft Update to RFC 3455 October 2005 5. Security considerations This document makes a number of small changes to some headers defined in RFC3455 [3]. It is not considered that these changes impact the initial security analysis performed in RFC3455 [3]. Drage Expires April 20, 2006 [Page 9]
Internet-Draft Update to RFC 3455 October 2005 6. IANA considerations This document requires no action by IANA. 7. References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997. [2] Rosenberg, J., "SIP: Session Initiation Protocol", June 2002. [3] Garcia-Martin, M., "Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3rd-Generation Partnership Project (3GPP)", January 2003. [4] Barnes, M., "An Extension to the Session Initiation Protocol for Request History Information", January 2005. Drage Expires April 20, 2006 [Page 10]
Internet-Draft Update to RFC 3455 October 2005 Author's Address Keith Drage Lucent Technologies Optimus, Windmill Hill Business Park Swindon, Wilts UK Email: drage@lucent.com Drage Expires April 20, 2006 [Page 11]
Internet-Draft Update to RFC 3455 October 2005 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. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. 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. Copyright Statement Copyright (C) The Internet Society (2005). 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. Drage Expires April 20, 2006 [Page 12]
