Network Working Group M. Mohali Internet-Draft Orange Updates: RFC4458 (if approved) October 26, 2014 Intended status: Informational Expires: April 29, 2015 Session Initiation Protocol (SIP) Cause URI parameter for Service Number translation draft-mohali-dispatch-cause-for-service-number-00 Abstract [RFC4458] defines a "cause" URI parameter as having predefined values for Redirecting reasons as a mapping from ITU-T Q.732.2-5 Redirecting Reasons. The "cause" URI parameter is to be used in SIP or SIPs URI. In particular, it may appear in the History-Info header defined in [RFC7044] that MUST be added in retargeted requests. This specification creates a new predefined value for cases when the retargeting is caused by a specific service action leading to a called number translation. This document updates [RFC4458]. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on April 29, 2015. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of Mohali Expires April 29, 2015 [Page 1] Internet-Draft Cause for service number translation October 2014 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction The History-Info header [RFC7044] provides a mechanism to capture the history information associated with a Session Initiation Protocol (SIP) request. This capability enables many enhanced services by providing the information as to how and why a SIP request arrives at a specific application or user. To be able to filter specific entries among the history information, tags have been defined in [RFC7044]. For instance, the "mp" tag allows identifying, retargeting that are result of a decision made by a particular type of application or that an initial request has been retargeted as a result of an application decision in a general manner. The "mp" tag is added when the target was determined based on a mapping to a user other than the target user associated with the Request-URI being retargeted. Additionally, a mechanism has been defined in [RFC4458] to add a "cause" parameter in the target URI to be able to identify retargeting due to the call forwarding supplementary services form other retargetings. This "cause" parameter has defined values equivalent to the TDM Redirecting reasons. There is no solution to identify other reasons for retargeting than call forwarding service whereas some others already exist in PSTN/ ISDN. In particular, it is the case for IN services number translation identified in ISUP by the "called IN number" and the "original called IN number". Cause is a URI parameter that is used to indicate the service that the User Agent Server (UAS) receiving the message should perform. Mohali Expires April 29, 2015 [Page 2] Internet-Draft Cause for service number translation October 2014 This specification proposes a solution for well-known services such as premium or tool free services that are doing retagertings. 2. Problem Statement A mechanism is required to identify URIs that are issued form a retargeting by a specific service similar to PSTN/ISDN IN services. This mechanism needs to cover at least the IN services that can be identified in the ISUP signaling in the "called IN number" and "original called IN number" optional parameters defined in [ITU-T_Q.763] and used in ISUP/INAP interworking as described in [ITU-T_Q.1600]. 3. Solution A new alternative value for the "cause" parameter of the 'sip:' or 'sips:' URI schemes is defined. This value may be used in a 'sip:' or 'sips:' URI inserted in the History-Info header [RFC7044] when the "mp" tag is present and the URI is issued form a retargeting by a specific service similar to PSTN/ISDN IN services. As defined in [RFC4458], the cause URI parameter MUST be encoded in the target URI when generated by the service. The ABNF grammar [RFC5234] for the cause-param and target-param parameters is reminded below as it has been subject to Errata [ID: 1409] in [RFC4458]. The Status-Code is defined in [RFC3261]. target-param = "target=" pvalue cause-param = "cause=" Status-Code The following value for this URI parameter is added to the existing ones: +---------------------------------+-------+ | Service Type | Value | +---------------------------------+-------+ | Service number translation | 380 | +---------------------------------+-------+ Mohali Expires April 29, 2015 [Page 3] Internet-Draft Cause for service number translation October 2014 4. Example In this section an example will be provided to illustrate the application of hte new cause-param value. History-Info: ;index=1, ;index=1.1;mp=1 5. IANA Considerations [RFC3969] defines a 'sip:' or 'sips:' URI Parameter sub registry. [RFC4458] defines a "cause" parameter specified as having predefined values. This RFC defines a new value for the "cause" parameter: 480. This RFC has been added to the references listed for the "cause" the "SIP/SIPS URI Parameters" sub-registry in for the "cause" parameter. Parameter Name Predefined Values References -------------- ----------------- ------------------ cause Yes [RFC4458][RFCxxxx] 6. Security Considerations The security considerations in [RFC4458] apply. A privacy service that performs the "Privacy: header" Service [RFC3323] must remove the cause URI parameter from the URI. Privacy of the parameters, when they form part of a URI within the History- Info header field, is covered in [RFC7044]. 7. References 7.1. Normative References [RFC2119] "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [RFC3261] "SIP: Session Initiation Protocol", RFC 3261, June 2002. [RFC3323] "A Privacy Mechanism for the Session Initiation Protocol (SIP)", RFC 3323, November 2002. [RFC3969] "The Internet Assigned Number Authority (IANA) Uniform Resource Identifier (URI) Parameter Registry for the Session Initiation Protocol (SIP)", December 2004. Mohali Expires April 29, 2015 [Page 4] Internet-Draft Cause for service number translation October 2014 [RFC7044] "An Extension to the Session Initiation Protocol (SIP) for Request History Information", RFC 7044, February 2014. 7.2. Informative References [ITU-T_Q.1600] ITU-T Recommendation Q.1600, "Signalling System No. 7 - Interaction between ISUP and INAP", September 1997. [ITU-T_Q.763] ITU-T Recommendation Q.763, "Signalling System No. 7 - ISDN User Part formats and codes.", December 1999. [RFC4458] "Session Initiation Protocol (SIP) URIs for Applications such as Voicemail and Interactive Voice Response (IVR)", RFC 4458, April 2006. [RFC5234] "Augmented BNF for Syntax Specifications: ABNF", RFC 5234, January 2008. Author's Address Marianne Mohali Orange 38-40 rue du General Leclerc Issy-Les-Moulineaux Cedex 9 92794 France Phone: +33 1 45 29 45 14 Email: marianne.mohali@orange.com Mohali Expires April 29, 2015 [Page 5]