IPTEL WG R. Mahy, Ed. Internet-Draft Airespace Expires: August 22, 2005 February 21, 2005 The Calling Party's Category tel URI Parameter draft-mahy-iptel-cpc-02.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. 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 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. This Internet-Draft will expire on August 22, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document specifies a new parameter for the tel URI that represents the Calling Party's Category, a parameter used in SS7 ISUP signaling. 1. Introduction SS7 ISUP [3] defines a Calling Party's Category (CPC) parameter that characterizes the station used to originate a call and carries other Mahy Expires August 22, 2005 [Page 1] Internet-Draft CPC tel URI February 2005 important state that can describe the originating party. When telephone numbers are contained in URIs, such as the tel URI [1], it may be desirable to communicate any CPC associated with that telephone number or, in the context of a call, the party calling from it. Note that in some networks (including North America), the Originating Line Information (OLI) parameter is used to carry this information in ANSI ISUP [6] rather than the CPC parameter. Legacy multifrequency (MF) signaling networks carry this information in the ANI II Digits [7]. The tel URI parameter specified in this document is designed to carry data from these sources as well. 2. Parameter Definition The Calling Party's Category is represented as a tel URI parameter. The ABNF [2] syntax is as follows: cpc = cpc-tag "=" cpc-value cpc-tag = "cpc" cpc-value = "ordinary" / "prison" / "police" / "test" "operator" / "payphone" / "unknown" / "hospital" / "cellular" / "cellular-roaming" / genvalue genvalue = 1*(alphanum / "-" / "." ) The semantics of these Calling Party's Category values are described below: ordinary: The caller has been identified, and has no special features. test: This is a test call that has been originated as part of a maintenance procedure. operator: The call was generated by an operator position. payphone: The calling station is a payphone. prison: The calling station is in a prison. hotel: The calling station is in a hotel or motel. hospital: The calling station is in a medical facility. police: The calling station is associated with a branch of law enforcement. cellular: The calling station is a radio-telephone operating in its home network. cellular-roaming: The calling station is a radio-telephone roaming in another network unknown: The CPC could not be ascertained. An example of the syntax of the CPC parameter (in a small fragment of a SIP [4] message) is given below: Mahy Expires August 22, 2005 [Page 2] Internet-Draft CPC tel URI February 2005 INVITE sip:bob@biloxi.example.com SIP/2.0 To: "Bob" From: ;tag=1928301774 3. Usage The CPC is generally useful only when describing the originator of a telephone call. Therefore, when this parameter is used in an application such as SIP, it is recommended that the parameter be applied to URIs that characterize the originator of a call (such as a SIP URI or tel URI in the From header field of a SIP message). Note that many Calling Party's Category values from the PSTN were intentionally excluded from the cpc parameter as they are either meaningless outside of the PSTN or can be represented using another existing concept. For example, the language of an operator can be expressed more richly using the Accept-Language header in SIP than in the cpc parameter. Similarly the priority of a call is a characteristic of the call and not the calling party. It is anticipated that this URI parameter will be used primarily by gateways that interwork ISUP networks with SIP networks. Various SIP network intermediaries might consult the CPC as they make routing decisions, although no specific behavior is prescribed in this document. While no specific mapping of the various ISUP parameters that contain CPC data is offered in this document, creating such a mapping would be trivial. If the CPC parameter is not present, consumers of the CPC should treat the URI as if it specified a CPC of "ordinary". At most, one instance of the CPC can be associated with a particular URI. 4. Security Considerations The information contained in the CPC parameter may be of a private nature, and it may not be appropriate for this value to be revealed to the destination user (typically it would not be so revealed in the PSTN). For more information about privacy issues in SIP see RFC3323 [5]. Otherwise, this mechanism adds no new security considerations to those discussed in [1]. 5. IANA Considerations This document requires no action by IANA. Mahy Expires August 22, 2005 [Page 3] Internet-Draft CPC tel URI February 2005 6. Contributors and Acknowledgments The original version of this document was written by Jon Peterson. Thanks to Takuya Sawada for a detailed review. 7. References 7.1 Normative References [1] Schulzrinne, H., "The tel URI for Telephone Numbers", RFC 3966, December 2004. [2] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. [3] International Telecommunications Union, "Recommendation Q.763: Signalling System No. 7: ISDN user part formats and codes", December 1999, . 7.2 Informational References [4] 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. [5] Peterson, J., "A Privacy Mechanism for the Session Initiation Protocol (SIP)", RFC 3323, November 2002. [6] American National Standards Institute, "ANSI T1.113-2000, Signaling System No. 7, ISDN User Part", 2000, . URIs [7] Author's Address Rohan Mahy (editor) Airespace 110 Nortech Pkwy San Jose, CA 95134 USA EMail: rohan@ekabal.com Mahy Expires August 22, 2005 [Page 4] Internet-Draft CPC tel URI February 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. 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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. 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. Mahy Expires August 22, 2005 [Page 5]