Internet Engineering Task Force SIP WG Internet Draft G. Camarillo Ericsson draft-ietf-sip-uri-parameter-reg-02.txt June 16, 2004 Expires: December 2004 The Internet Assigned Number Authority (IANA) Universal Resource Identifier (URI) Parameter Registry for the Session Initiation Protocol (SIP) STATUS OF THIS MEMO By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. 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. Abstract This document creates an IANA registry for SIP and SIPS URI parameters, and their values. It also lists the already existing parameters to be used as initial values for that registry. G. Camarillo [Page 1] Internet Draft SIP June 16, 2004 Table of Contents 1 Introduction ........................................ 3 2 Terminology ......................................... 3 3 Use of the Registry ................................. 3 4 IANA Considerations ................................. 4 4.1 SIP and SIPS URI Parameters Sub-Registry ............ 4 4.2 Registration Policy for SIP and SIPS URI Parameters . 5 5 Security Considerations ............................. 5 6 Acknowledgements .................................... 5 7 Authors' Addresses .................................. 5 8 Normative References ................................ 6 9 Informative References .............................. 6 G. Camarillo [Page 2] Internet Draft SIP June 16, 2004 1 Introduction RFC3261 [1] allows new SIP URI and SIPS URI parameters, and new parameter values to be defined. However, RFC3261 omitted an IANA registry for them. This document creates such a registry. RFC 3427 [2] documents the process to extend SIP. This document updates RFC 3427 by specifying how to define and register new SIP and SIP URI parameters and their values. 2 Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [3] and indicate requirement levels for compliant SIP implementations. 3 Use of the Registry SIP and SIPS URI parameters and values for these parameters MUST be documented in a standards-track RFC in order to be registered by IANA. This documentation MUST fully explain the syntax, intended usage, and semantics of the parameter. The intent of this requirement is to assure inetroperability between independent implementations, and to prevent accidental namespace collisions between implementations of dissimilar features. Note that this registry, unlike other protocol registries, only deals with parameters and parameter values defined in RFCs (i.e., it lacks a vendor-extension tree). RFC 3427 [2] documents concerns with regards to new SIP extensions which may be damaging towards security, greatly increase the complexity of the protocol, or both. New parameters and parameter values need to be documented in RFCs as a result of these concerns. RFCs defining SIP URI, SIPS URI parameters, or parameter values MUST register them with IANA as described below. Registered SIP and SIPS URI parameters and their values are to be considered "reserved words". In order to preserve interoperability, registered parameters MUST be used in a manner consistent with that described in their defining RFC. Implementations MUST NOT utilize "private" or "locally defined" URI parameters that conflict with registered parameters. Note that although unregistered SIP and SIPS URI parameters may be used in implementations, developers are cautioned G. Camarillo [Page 3] Internet Draft SIP June 16, 2004 that usage of such parameters is risky. New SIP and SIPS URI parameters and new values for them may be registered at any time, and there is no assurance that these new registered URI parameters will not conflict with unregistered parameters currently in use. Some SIP and SIPS URI parameters only accept a set of predefined parameter values. For example, a parameter indicating the transport protocol in use may only accept as valid values the predefined tokens TCP, UDP, and SCTP. Registering all parameter values for all SIP and SIPS URI parameters of this type would require a large number of subregistries. Instead, we have chosen to register URI parameter values by reference. That is, the entry in the URI parameter registry for a given URI parameter contains references to the RFCs defining new values of the parameter. References to RFCs defining parameter values appear in brackets in the registry. So, the SIP and SIPS URI parameter registry contains a column that indicates whether or not each parameter only accepts a set of predefined values. Implementers of parameters with a "yes" in that column need to find all the valid parameter values in the RFCs provided as references. 4 IANA Considerations Section 27 of RFC 3261 [1] creates an IANA registry for method names, header field names, warning codes, status codes, and option tags. This specification instructs the IANA to create a new sub-registry under http://www.iana.org/assignments/sip-parameters: o SIP/SIPS URI Parameters 4.1 SIP and SIPS URI Parameters Sub-Registry New SIP and SIPS URI parameters and new parameter values are registered by the IANA. When registering a new SIP or SIPS parameter or a new value for a parameter, the following information MUST be provided. o Name of the parameter. o Whether the parameter only accepts a set of predefined values. o Reference to the RFC defining the parameter and to any RFC that defines new values for the parameter. References to RFCs defining parameter values appear in brackets in the registry. Table 1 contains the initial values for this sub-registry. G. Camarillo [Page 4] Internet Draft SIP June 16, 2004 Parameter Name Predefined Values Reference ____________________________________________ comp Yes RFC 3486 lr No RFC 3261 maddr No RFC 3261 method Yes RFC 3261 transport Yes RFC 3261 ttl No RFC 3261 user Yes RFC 3261 Table 1: IANA SIP and SIPS URI parameter sub-registry Note that any given parameter name is registered both as a SIP and as a SIPS URI parameter. Still, some parameters may not apply to one of the schemes. We have chosen to register any parameter as both SIP and SIPS URI parameter anyway to avoid having two parameters with the same name, one applicable to SIP URIs and one to SIPS URIs, but with different semantics. Implementors are urged to read the parameter specifications for a detailed description of the semantics of any parameter. 4.2 Registration Policy for SIP and SIPS URI Parameters As per the terminology in RFC 2434 [4], the registration policy for SIP and SIPS URI parameters shall be "Specification Required". For the purposes of this registry, the parameter for which IANA registration is requested MUST be defined by a standards-track RFC. 5 Security Considerations There are no security considerations associated to this document. 6 Acknowledgements Jonathan Rosenberg, Henning Schulzrinne, Rohan Mahy, Dean Willis, and Allison Mankin provided useful comments. 7 Authors' Addresses Gonzalo Camarillo Ericsson Advanced Signalling Research Lab. FIN-02420 Jorvas Finland electronic mail: Gonzalo.Camarillo@ericsson.com G. Camarillo [Page 5] Internet Draft SIP June 16, 2004 8 Normative References [1] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. R. Johnston, J. Peterson, R. Sparks, M. Handley, and E. Schooler, "SIP: session initiation protocol," RFC 3261, Internet Engineering Task Force, June 2002. [2] A. Mankin, S. Bradner, R. Mahy, D. Willis, J. Ott, and B. Rosen, "Change process for the session initiation protocol (SIP)," RFC 3427, Internet Engineering Task Force, Dec. 2002. [3] S. Bradner, "Key words for use in RFCs to indicate requirement levels," RFC 2119, Internet Engineering Task Force, Mar. 1997. [4] T. Narten and H. Alvestrand, "Guidelines for writing an IANA considerations section in RFCs," RFC 2434, Internet Engineering Task Force, Oct. 1998. 9 Informative References 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 IETF's procedures with respect to rights in IETF 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. G. Camarillo [Page 6] Internet Draft SIP June 16, 2004 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 (2004). 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. G. Camarillo [Page 7]