RFC 3508

H.323 Uniform Resource Locator (URL) Scheme Registration

📅 published April 2003, from ietf

RFC 3508: H.323 URL Scheme Registration 💖

  • Network Working Group 🌸
  • Request for Comments: 3508 ✨
  • Author: O. Levin (Orit Levin), RADVISION 👑
  • Category: Informational 🎀
  • Date: April 2003 📅
  • Obsoletes / Updates: none listed in the title block 🦋

Status of This Memo 💅

This memo gives information to the Internet community. It is not an Internet standard of any kind, and distribution of it is unlimited. 🫶

Copyright (C) The Internet Society (2003). All Rights Reserved. 💜

Abstract ✨

Okay so ITU-T Recommendation H.323 version 4 brought in an H.323-specific Uniform Resource Locator (URL). This document copies the H323-URL definition from H.323 and publishes it as an RFC, so it's easier to find and easier to register with the Internet Assigned Numbers Authority (IANA). 🔥

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 BCP 14, RFC 2119 [2]. 💖

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........................................3
6. IANA Considerations............................................4
References........................................................4
Acknowledgments...................................................5
Author's Address..................................................5
Full Copyright Statement..........................................6

1. Introduction 🌸

ITU-T Recommendations H.323 [3] and H.225.0 [4] define a system for multimedia communication services over packet-based networks. H.225.0 [4] defines an alias type that carries any standard Uniform Resource Locator (URL). H.323 version 4 [3] then introduced an H.323-specific URL, which can be used to resolve the address of a network entity that H.323 calls can be directed to. It's giving main character energy 👑

This document copies the H323-URL definition from ITU-T recommendation H.323 [3] and publishes it as an RFC for easier access and IANA registration. 🦋

2. URL Scheme Formal Syntax Definition and Character Encoding 💅

The H.323 URL is defined in ABNF, shown below. It uses the Core Rules from 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 [ "." ]
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, characters with a numeric value below 0x80 are case insensitive, and characters with a numeric value at or above 0x80 are case sensitive. 🌈

The character set and case sensitivity of "url-parameter" are specified in each parameter definition. ✨

3. Intended Usage 🦋

The H.323 URL helps an entity resolve the address of another H.323 entity. An "entity" can be a user, a device, or a service. The "user" part of the URL names an alias for the entity and says nothing about where the entity is located. The "hostport" is the domain name of an Endpoint, Gatekeeper, Border Element, or other functional element that H.323 calls can be directed to, or that services can be performed through. 💖

4. Applications and/or protocols, which may use H.323 URL scheme 🧚

H.323 URLs can be carried by other protocols, such as SIP [6] or TRIP [9]. They can also show up inside web pages or XML data, where H.323 entities can use them to start calls or perform services. 🔥

5. Security Considerations 🛡️

When an H.323 URL is carried within H.225.0 [4] messages, security is handled by the H.235 security framework [5]. When an H.323 URL is carried within other protocols (such as SIP [6]), security is handled within that corresponding protocol. 💜

Security is a big deal here! Generally, security for H.323 URL usage and carriage should be handled within H.323 or other relevant protocols. It is not within the scope of this document. 💀

6. IANA Considerations 👑

This document exists to serve as a reference point for registering the H.323 URL scheme with IANA. 🎀

Once the URL is registered with IANA, there's no way another scheme called "h323" gets duplicated. This document copies the exact H323-URL definition published in ITU-T Recommendation H.323 [3]. 🌸

Registration Template:

   URL scheme name: h323

   URL scheme syntax: Section 2 of RFC 3508

   Character encoding considerations: Section 2 of RFC 3508

   Intended usage: Section 3 of RFC 3508

   Applications and/or protocols which use this scheme: Section 4 of
   RFC 3508

   Interoperability considerations: None.  (Section 2 of RFC 3508
   contains the first version of "h323" URL definition.)

   Security considerations: Section 5 of RFC 3508

   Relevant publications: [3] and [4]

   Contact: Orit Levin, orit@radvision.com

   Author/Change Controller: IESG

References 📚

  • [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 🫶
  • [2] Crocker, D., Editor, and P. Overell "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, 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] 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. 🦋
  • [7] Yergeau, F., "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, J., Salama, H. and M. Squire, "Telephony Routing over IP (TRIP)", RFC 3219, January 2002. 🧚

Acknowledgments 💖

This document is prepared and posted on behalf of SG-16 ITU-T. Thanks so much to Paul E. Jones, Robert Callaghan and Cullen Jennings for their comments and active help! 🫶

Author's Address 🎀

Orit Levin
RADVISION
266 Harristown Road
Glen Rock, NJ USA

Phone:  +1-201-689-6330
EMail:  orit@radvision.com

Copyright (C) The Internet Society (2003). All Rights Reserved. 💜

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However, this document itself may not be modified in any way. That includes removing the copyright notice or the references to the Internet Society or other Internet organizations. The exceptions are when it's needed to develop Internet standards, in which case the copyright procedures in the Internet Standards process must be followed, or when it's translated into a language other than English. 🦋

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