The Internet Assigned Number Authority (IANA) tel Uniform Resource Identifier (URI) Parameter Registry
RFC 5341

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Network Working Group                                        C. Jennings
Request for Comments: 5341                                 Cisco Systems
Updates: 3966                                                 V. Gurbani
Category: Standards Track              Bell Laboratories, Alcatel-Lucent
                                                          September 2008

             The Internet Assigned Number Authority (IANA)
        tel Uniform Resource Identifier (URI) Parameter Registry

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Abstract

   This document creates an Internet Assigned Number Authority (IANA)
   registry for tel Uniform Resource Identifier (URI) parameters and
   their values.  It populates the registry with the parameters defined
   in the tel URI specification, along with the parameters in tel URI
   extensions defined for number portability and trunk groups.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 2
   3.  Use of the Registry . . . . . . . . . . . . . . . . . . . . . . 2
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
     4.1.  tel URI Parameters Registry . . . . . . . . . . . . . . . . 3
     4.2.  Registration Policy for tel URI Parameters  . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 5

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RFC 5341          IANA Registry for TEL URI Parameters    September 2008

1.  Introduction

   The tel URI (RFC 3966 [1]), defines a URI that can be used to
   represent resources identified by telephone numbers.  The tel URI,
   like many other URIs, provides extensibility through the definition
   of new URI parameters and new values for existing parameters.
   However, RFC 3966 did not specify an IANA registry where such
   parameters and values can be listed and standardized.  This
   specification creates such a registry.

2.  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 [2].

3.  Use of the Registry

   The tel URI parameters and values for these parameters MUST be
   documented in a RFC or other permanent and readily available public
   specification in order to be registered by IANA.  This documentation
   MUST fully explain the syntax, intended usage, and semantics of the
   parameter.  The intent of this requirement is to assure
   interoperability between independent implementations, and to prevent
   accidental namespace collisions between implementations of dissimilar
   features.

   Documents defining tel URI parameters or parameter values MUST
   register them with IANA, as described in Section 4.  The IANA
   registration policy for such parameters is "Specification Required,
   Designated Expert," and is further discussed in Section 4.2.

   Some tel URI parameters only accept a set of predefined parameter
   values while others can take any value.  There are also parameters
   that do not have any value; they are used as flags.

   Those URI parameters that take on predefined values typically take on
   a large number of values.  Registering each of those values, or
   creating a sub-registry for each such parameter is not appropriate.
   Instead, we have chosen to register URI parameter values by
   reference.  That is, the entry in the URI parameter registry for a
   given URI parameter contains references to the RFCs defining new
   values of that parameter.

   Accordingly, the tel URI parameter registry contains a column that
   indicates whether or not each parameter accepts a value.  The column
   may contain "No value" or "Constrained".  A "Constrained" in the
   column implies that certain predefined values exist for this

Jennings & Gurbani          Standards Track                     [Page 2]
RFC 5341          IANA Registry for TEL URI Parameters    September 2008

   parameter and the accompanying RFC or other permanent and readily
   available public specification should be consulted to find out the
   accepted set of values.  A "No Value" in the column implies that the
   parameter is used either as a flag, or does not have a set of