IPTEL WG Internet Draft O. Levin Document: RADVISION draft-levin-iptel-h323-url-scheme-05.txt Expires: May 2003 November 2002 H.323 URL Scheme Registration with IANA Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [1]. 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 IETF document reproduces the H323-URL definition found in ITU-T Recommendation H.323 [3] and is published as an RFC for ease of access and IANA registration. Conventions used in this document 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 [2]. O. Levin Expires - May 2003 [Page 1] H.323 URL Scheme Registration with IANA November 2002 Table of Contents 1. Introduction...................................................2 2. URL Scheme Formal Syntax Definition and Character Encoding.....2 3. Intended Usage.................................................3 4. Applications and/or protocols, which may use H.323 URL scheme..3 5. Security Considerations........................................4 6. IANA Considerations............................................4 References........................................................5 Acknowledgments...................................................5 Author's Addresses................................................5 Copyright Notice..................................................6 1. Introduction ITUûT Recommendations H.323 [3] and H.225.0 [4] define a system for multimedia communications services over packet based networks. H.225.0 [4] defines an alias type for carrying any standard Uniform Resource Locator (URL). H.323 version 4 [3] introduced an H.323- specific URL, which may be used to help facilitate the termination of calls or redirection of a calling endpoint. This IETF document reproduces the H323-URL definition found in ITU-T Recommendation H.323 [3] and is published as an RFC for ease of access and IANA registration. 2. URL Scheme Formal Syntax Definition and Character Encoding The H323-URL definition is composed of two parts: the "user" and the "hostport". The user specifies an alias for the entity, such as a user or a service, without carrying any information about the location of the entity. The "hostport", on the other hand, is the domain name of the Endpoint, Gatekeeper, or Border Element. The H.323 URL is defined in ABNF as shown below. Note that it utilizes the Core Rules specified in section 6.1 of [2]. H323-URL = "h323:" address [ url-parameters ] address = user / "@" hostport / user "@" hostport user = 1*(%x21-24 / %x26-3F / %x41-7F / escaped) ; The symbols "%", "@", and symbols with ; a character value below 0x21 may be ; represented as escaped sequences. hostport = host [ ":" port] host = hostname / IPv4address / IPv6reference hostname = *( domainlabel "." ) toplabel [ "." ] O. Levin Expires - May 2003 [Page 2] H.323 URL Scheme Registration with IANA November 2002 domainlabel = alphanum / alphanum *( alphanum / "-" ) alphanum toplabel = ALPHA / ALPHA *( alphanum / "-" ) alphanum IPv4address = 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT IPv6reference = "[" IPv6address "]" IPV6address = hexpart [ ":" IPv4address ] hexpart = hexseq / hexseq "::" [ hexseq ] / "::" [ hexseq ] hexseq = hex4 *( ":" hex4 ) hex4 = 1*4HEXDIG port = 1*DIGIT url-parameters = *( ";" url-parameter ) url-parameter = 1*(%x21-24 / %x26-3A / %x3C-7F / escaped) ; Specific parameter definitions are for ; further study. ; The symbols "%", ";", and symbols ; with a character value below 0x21 may be ; represented as escaped sequences. alphanum = ALPHA / DIGIT escaped = "%" HEXDIG HEXDIG The host is case insensitive. The "user" is a Unicode [8] string that shall be UTF-8 [7] encoded and then escaped as necessary. In the "user" field, the characters with a numeric value below 0x80 are case insensitive and the characters with a numeric value above or equal to 0x80 are case sensitive. The character set and case sensitivity of the "url-parameter" is specified in each parameter definition. 3. Intended Usage The H.323 URL is intended to help an entity resolve the address of another H.323 entity, where an "entity" may be a user, a device, or a service. The "user" portion of the URL specifies an alias for the entity, without carrying any information about the location of the entity. The "hostport", on the other hand, is the domain name of an Endpoint, Gatekeeper, Border Element, or other functional element to which H.323 calls may be directed or for which services may be performed. 4. Applications and/or protocols, which may use H.323 URL scheme H.323 URLs may be carried by other protocols, such as SIP [6] or TRIP [9]. H.323 URLs may be also contained within web pages or within XML data, which may be utilized by H.323 entities in order to initiate calls or perform services. O. Levin Expires - May 2003 [Page 3] H.323 URL Scheme Registration with IANA November 2002 5. Security Considerations When H.323 is URL is carried within H.225.0 [4] messages, security is addressed by the H.235 security framework [5]. When H.323 URL is carried within other protocols (such as SIP [6]), the security is addressed within the corresponding protocol. In general, security, as it relates to the usage and carriage of the H.323 URLs, is considered as an issue that should be addressed within scope of H.323 or other relevant protocols and is not within the scope of this document. 6. IANA Considerations The purpose of this document is serving as a reference point for the purposes of registering the H.323 URL scheme with IANA. Having the URL registered with IANA will ensure that there is no duplication of the URL scheme "h323". This document reproduces the exact H323-URL definition as published in ITU-T Recommendation H.323 [3]. [NOTE to IANA: Replace RFC XXXX with the RFC number of this document] Registration Template URL scheme name: h323 URL scheme syntax: Section 2 of RFC XXXX Character encoding considerations: Section 2 of RFC XXXX Intended usage: Section 3 of RFC XXXX Applications and/or protocols which use this scheme: Section 4 of RFC XXXX Interoperability considerations: None. (Section 2 of RFC XXXX contains the first version of "h323" URL definition.) Security considerations: Section 5 of RFC XXXX Relevant publications: [3] and [4] Contact: Orit Levin, orit@radvision.com Author/Change Controller: IESG O. Levin Expires - May 2003 [Page 4] H.323 URL Scheme Registration with IANA November 2002 References 1 Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 2 Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, Internet Mail Consortium and Demon Internet Ltd., November 1997 3 ITU-T Recommendation H.323v.4 "Packet-based multimedia communications systems", November 2000 4 ITU-T Recommendation H.225.0 "Call signalling protocols and media stream packetization for packet-based multimedia communication systems", November 2000 5 ITU-T Recommendation H.235 "Security and Encryption for H Series (H.323 and other H.245 based) multimedia terminals", November 2000 6 J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. 7 F. Yergeau, "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998 8 ISO/IEC 10646-1:1993, Information technology "Universal Multiple-Octet Coded Character Set (USC)" Part 1: Architecture and Basic Multilingual Plane 9 Rosenberg/Salama/Squire, "Telephony Routing over IP (TRIP)", RFC 3219, Jan 2002 Acknowledgments This document is prepared and posted on behalf of SG-16 ITU-T. I wish to thank Paul E. Jones, Robert Callaghan and Cullen Jennings for their comments and active help. Author's Addresses Orit Levin RADVISION 266 Harristown Road Glen Rock, NJ USA O. Levin Expires - May 2003 [Page 5] H.323 URL Scheme Registration with IANA November 2002 Email: orit@radvision.com Phone: +1-201-689-6330 Copyright Notice "Copyright (C) The Internet Society (date). All Rights Reserved. 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