Network Working Group Vikram Nair INTERNET-DRAFT Flextronics Software Systems Expires: September 9, 2005 March 2005 MIME media types for SCCP and TCAP Objects draft-nair-sccp-tcap-mime-00.txt 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, or will be 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/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract This document describes MIME types as per the rules defined in RFC 2048 [2] for application/SCCP and application/TCAP objects, for use in SIP applications. These MIME definitions will be typically used in deployments where interworking to the PSTN is required for call related and non-call related messages exchanged using services of SCCP and TCAP SS7 stack layers. Terminology 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 RFC 2119 [9]. nair, et al. [Page 1] INTERNET-DRAFT Expires: September 29, 2005 1. Introduction SCCP (Signaling Connection Control Part) and TCAP (Transaction Capability Part) are protocols used between SS7 nodes. This document describes MIME types for application/SCCP and application/TCAP objects for use in SIP applications as per rules defined in [2]. There are scenarios where, while interworking between SS7 and SIP networks, not all parameters relevant in SS7 network could be interworked onto SIP networks. In such configurations transporting SCCP or TCAP encoded signaling information between SIP entities as part of the payload of SIP messages would help in realizing next generation services using the legacy SS7 infrastructure. In SS7 protocol(s) stack, TCAP layer uses services provided by SCCP layer. This document however, defines MIME types for use with either SCCP or TCAP. By using TCAP MIME directly instead of SCCP MIME MAY help implementations save upon processing bandwidth provided the parameters in SCCP portion are not important to realize the service. This is intended to be an IETF approved MIME type, and to be defined through an RFC. NOTE: usage of SCCP or TCAP within SIP is neither endorsed nor recommended as a result of this MIME registration. 2. Proposed new media types SCCP / TCAP messages are composed of binary data that is transparent to SIP processing. The best way to encode these is to use binary encoding. This is in conformance with the restrictions imposed on the use of binary data for MIME (RFC 2045 [4]). It should be noted that the rules mentioned in the RFC 2045 apply to Internet mail messages and not to SIP messages. Binary has been preferred over Base64 encoding because the latter would only result in adding bulk to the encoded messages and possibly be more costly in terms of processing power. 2.1 SCCP Media Type The application/SCCP media type is defined by the following information: Media type name: application Media subtype name: SCCP Required parameters: version nair, et al. [Page 2] INTERNET-DRAFT Expires: September 29, 2005 Optional parameters: None Encoding scheme: binary Security considerations: See section 4. The SCCP message is encapsulated beginning with the routing label parameter in SCCP PDU. The 'version' parameter as defined in [7], SHALL be used to identify the SCCP protocol version being transported as MIME e.g. itu-t 03/93 Q.711. The string values for version parameter MAY be administered on bilateral basis. This specification puts no constraints on suitable values that may be used for 'version' parameter. Content-Disposition header [5] may be included to describe how the encapsulated SCCP is to be processed. The rules defined in [7] for usage of Content-Disposition header for ISUP MIMEs SHALL be followed for SCCP MIME types as well. A sample illustration of Content-Type and Content-Disposition header for SCCP MIME object is presented below Content-Type: application/SCCP; version=itu-1993 Content-Disposition: signal; handling=optional 2.2 TCAP Media Type The application/TCAP media type is defined by the following information: Media type name: application Media subtype name: TCAP Required parameters: version Optional parameters: None Encoding scheme: binary Security considerations: See section 4. The TCAP message is encapsulated beginning with the Transaction Portion of TCAP PDU. The 'version' parameter as defined in [7], SHALL be used to identify the TCAP protocol version being transported as MIME e.g. itu-t 03/93 Q.771. The string values for version parameter SHALL be administered on bilateral basis. This specification puts no constraints on suitable values that may be used for 'version' parameter. Content-Disposition header [5] may be included to describe how the nair, et al. [Page 3] INTERNET-DRAFT Expires: September 29, 2005 encapsulated TCAP is to be processed. The rules defined in [7] for usage of Content-Disposition header for ISUP MIME SHALL be followed for TCAP MIME types as well. A sample illustration of Content-Type and Content-Disposition header for TCAP MIME object is presented below Content-Type: application/TCAP; version=itu-1993 Content-Disposition: signal; handling=optional 3. Illustrative examples The sections below illustrates the use of application/SCCP and application/TCAP MIME types in SIP messages. The binary portion shown in the examples below representing the SCCP or TCAP PDU are for illustration purpose only and are not the actual content for any SCCP or TCAP message. 3.1 SCCP This section illustrates the use of application/SCCP media type in a SIP NOTIFY message which has a SPIRITS Event notification [8] and an encapsulated SCCP UDT. Note that the two payloads are demarcated by the boundary parameter (specified in RFC 2046 [1]) which in the example has the value "unique-boundary-1". This is part of the specification of MIME multipart and is not related to the application/SCCP media type. NOTIFY sip:nair@host.example.com SIP/2.0 From: ;tag=asd6302240216 To: ;tag=8177-afd-991 Via: SIP/2.0/UDP notifier.myprovider.com;branch=z9hG4bK9innu7 Call-ID: 11442233@host.example.com Contact: CSeq: 200 NOTIFY Subscription-State: terminated;reason=fired Accept: application/spirits-event+xml Event: spirits-INDPs Allow-Events: spirits-INDPs, spirits-user-prof Content-Type: multipart/mixed; boundary=unique-boundary-1 Content-Length: ... --unique-boundary-1 nair, et al. [Page 4] INTERNET-DRAFT Expires: September 29, 2005 Content-Type: application/spirits-event+xml 6302240216 3125551212 --unique-boundary-1 Content-Type: application/SCCP; version=itu-1993; Content-Disposition: signal; handling=optional 01 00 49 00 00 03 02 00 07 04 10 00 33 63 21 43 00 00 03 06 0d 03 80 90 a2 07 03 10 03 63 53 00 10 0a 07 03 10 27 80 88 03 00 00 89 8b 0e 95 1e 1e 1e 06 26 05 0d f5 01 06 10 04 00 --unique-boundary-1-- 3.2 TCAP This section illustrates the use of application/TCAP media type in a SIP NOTIFY message which has a SPIRITS Event notification [8] and an encapsulated TCAP continue message. Note that the two payloads are demarcated by the boundary parameter (specified in RFC 2046 [1]) which in the example has the value "unique-boundary-1". This is part of the specification of MIME multipart and is not related to the application/TCAP media type. NOTIFY sip:nair@host.example.com SIP/2.0 From: ;tag=asd6302240216 To: ;tag=8177-afd-991 Via: SIP/2.0/UDP notifier.myprovider.com;branch=z9hG4bK9innu7 Call-ID: 11442233@host.example.com Contact: CSeq: 200 NOTIFY Subscription-State: terminated;reason=fired Accept: application/spirits-event+xml Event: spirits-INDPs Allow-Events: spirits-INDPs, spirits-user-prof Content-Type: multipart/mixed; boundary=unique-boundary-1 Content-Length: ... nair, et al. [Page 5] INTERNET-DRAFT Expires: September 29, 2005 --unique-boundary-1 Content-Type: application/spirits-event+xml 6302240216 3125551212 --unique-boundary-1 Content-Type: application/TCAP; version=itu-1993; Content-Disposition: signal; handling=optional 01 00 49 00 00 03 02 00 07 04 10 00 33 63 21 43 00 00 03 06 0d 03 80 90 a2 07 03 10 03 63 53 00 10 0a 07 03 10 27 80 88 03 00 00 89 8b 0e 95 1e 1e 1e 06 26 05 0d f5 01 06 10 04 00 --unique-boundary-1-- 4. Security considerations Information contained in SCCP and TCAP bodies may include sensitive customer information, potentially requiring use of encryption. Security mechanisms are provided in RFC 3261 [3] (SIP - Session Initiation Protocol) should be used as appropriate for both the SIP message and the encapsulated SCCP or TCAP body. 5. IANA considerations This document registers the "application/SCCP" and "application/TCAP" MIME media types. 6. Author Address Vikram Nair Flextronics Software Systems Electronic City, Gurgaon Harayana, India. EMail: vnair75@gmail.com 7. References [1] Freed, N. and N. Borenstein, "Multipurpose Internet Mail nair, et al. [Page 6] INTERNET-DRAFT Expires: September 29, 2005 Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996. [2] Freed, N., Klensin, J. and J. Postel, "Multipart Internet Mail Extensions (MIME) Part Four: Registration Procedures", BCP 13, RFC 2048, November 1996. [3] Rosenberg, et al, "Session Initiation Protocol (SIP)", RFC 3261, June 2002 [4] Freed, N. and N. Borenstein, "Multipart Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [5] Troost, R., Dorner, S. and K. Moore,"Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field", RFC 2183, August 1997. [6] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [7] Zimmerer, et al, "MIME media types for ISUP and QSIG objects" RFC 3204, December 2001 [8] Gurbani, et al, "The SPIRITS (Services in PSTN requesting Internet Services) Protocols, RFC 3910, October 2004 [9] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, Internet Engineering Task Force, March 1997. 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. nair, et al. [Page 7] INTERNET-DRAFT Expires: September 29, 2005 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. Full 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. 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. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. nair, et al. [Page 8]