Appsawg Z. Shelby Internet-Draft Sensinode Intended status: Standards Track March 5, 2012 Expires: September 6, 2012 The +exi Media Type Suffix draft-shelby-exi-registration-00 Abstract Efficient XML Interchange (EXI) is an XML representation technique specified by the W3C to provie a binary alternative to the standard text XML representation. This document defines a new Structure Syntax Suffix "+exi" for use in a specific class of protocols, where "exi" content-type encoding or the generic "application/exi" Media Type are not applicable. 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 September 6, 2012. Copyright Notice Copyright (c) 2012 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 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as Shelby Expires September 6, 2012 [Page 1] Internet-Draft The +exi Media Type Suffix March 2012 described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. When to Use the +exi Suffix . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5 Shelby Expires September 6, 2012 [Page 2] Internet-Draft The +exi Media Type Suffix March 2012 1. Introduction Efficient XML Interchange (EXI) [W3C.REC-exi-20110310] is an XML representation technique specified by the W3C to provie a binary alternative to the standard text XML representation. EXI is not a generic compression technique like gzip or deflate, but an encoding technique specifically for XML that uses either learnt or pre- informed schema information. This document defines a new Structure Syntax Suffix "+exi" for use in a specific class of protocols, where the "exi" content-type encoding or generic "application/exi" Media Type defined in [W3C.REC-exi-20110310] are not applicable. 2. When to Use the +exi Suffix The EXI standard already defines both an "exi" content-type encoding and an "application/exi" Media Type. This sections discusses when it is appropriate to use the new "+exi" Structured Syntax Suffix when registring a Media Type. Appendix F.1 of [W3C.REC-exi-20110310] clearly describes when the exi content-type encoding should be used: "Protocols that can identify and negotiate the content coding of XML information independent of its media type, SHOULD use the content coding "exi" (case- insensitive) to convey the acceptance or actual use of EXI encoding for XML information." Thus when a protocol depends on the media type to identify that the payload is EXI, it can make use of the "application/exi" Media Type defined in Appendix F.2 of [W3C.REC-exi-20110310]. This works particularly well for applications using EXI in a generic way, and in particular in non Schema-informed mode, where protocol specific information is not needed to process the payload, in particular the XML schema used. In these cases it is recommended to use the "application/exi" Media Type or "exi" content-type encoding. The "+exi" Structure Syntax Suffix defined in this document is appropriate for use with protocols that: o Make use of a Media Type to identify the semantics of the protocol payload, and offer more that one serialization of the payloads. For example, some protocols may offer JSON, XML and EXI representations. o Use EXI as a native encoding (without the use of XML as an interemediate) in Strict Schema-informed mode, and the base Media Shelby Expires September 6, 2012 [Page 3] Internet-Draft The +exi Media Type Suffix March 2012 Type indicates to the protocol the Schema that was used to produce the EXI grammar. 3. Security Considerations Security considerations are discussed in Section 4. 4. IANA Considerations This document requests registration of the Structured Syntax Suffix "+exi" as follows, following the registration template from Section 6.2 of [I-D.ietf-appsawg-media-type-regs]. Name: Efficient XML Interchange +suffix: "+exi" References: The EXI standard is defined in [W3C.REC-exi-20110310], in particular Schema-informed Grammars are defined in Section 8.5 and the "applicatio/exi" Media Type is defined in Appendix F.2. Encoding considerations: Binary Interoperability considerations: The registration of a Media Type using this suffix MUST reference the XML Schema that is used to encode/decode a payload identified by that Media Type. If multi versions of this Schema will evolve during the lifetime of the protocol, the protocol MUST either register multiple Media Types (one for each version) or use the Schema ID option of EXI to indicate the version of the Schema. Security considerations: The "+exi" suffix shares the same security considerations as XML, described in [RFC3023], Section 10. In addition, the security considerations discussed in the Media Type registration for "application/exi" apply as defined in Appendix F.2 of [W3C.REC-exi-20110310]. Contact: Apps Area Working Group (apps-discuss@ietf.org) Author/Change controller: The Apps Area Working Group has change control over this registration. Shelby Expires September 6, 2012 [Page 4] Internet-Draft The +exi Media Type Suffix March 2012 5. Acknowledgments This draft is the result of discussions on the Apps Area Working Group mailing list. 6. Changelog 7. References 7.1. Normative References [I-D.ietf-appsawg-media-type-regs] Klensin, J., Hansen, T., and N. Freed, "Media Type Specifications and Registration Procedures", draft-ietf-appsawg-media-type-regs-01 (work in progress), February 2012. [W3C.REC-exi-20110310] Kamiya, T. and J. Schneider, "Efficient XML Interchange (EXI) Format 1.0", World Wide Web Consortium Recommendation REC-exi-20110310, March 2011, . 7.2. Informative References [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media Types", RFC 3023, January 2001. Author's Address Zach Shelby Sensinode Kidekuja 2 Vuokatti 88600 FINLAND Phone: +358407796297 Email: zach@sensinode.com Shelby Expires September 6, 2012 [Page 5]