The Internet Assigned Number Authority (IANA) Header Field Parameter Registry for the Session Initiation Protocol (SIP)
draft-ietf-sip-parameter-registry-02

SIP Working Group G. Camarillo
Internet-Draft Ericsson
Expires: December 15, 2004 June 16, 2004
 The Internet Assigned Number Authority (IANA) Header Field Parameter
 Registry for the Session Initiation Protocol (SIP)
 draft-ietf-sip-parameter-registry-02.txt
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Copyright Notice
 Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
 This document creates an IANA registry for SIP header field
 parameters and parameter values. It also lists the already existing
 parameters and parameter values to be used as the initial entries for
 this registry.
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Table of Contents
 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
 3. Use of the Registry . . . . . . . . . . . . . . . . . . . . . 3
 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
 4.1 Header Field Parameters Sub-Registry . . . . . . . . . . . 4
 4.2 Registration Policy for SIP Header Field Parameters . . . 7
 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
 7. Normative References . . . . . . . . . . . . . . . . . . . . . 8
 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 8
 Intellectual Property and Copyright Statements . . . . . . . . 9
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1. Introduction
 RFC 3261 [3] allows new header field parameters and new parameter
 values to be defined. However, RFC3261 omitted an IANA registry for
 them. This document creates such a registry.
 RFC 3427 [4] documents the process to extend SIP. This document
 updates RFC 3427 by specifying how to define and register new SIP
 header field parameters and parameter values.
2. Terminology
 In this document, the key words "MUST", "MUST NOT", "REQUIRED",
 "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT
 RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as
 described in BCP 14, RFC 2119 [1] and indicate requirement levels for
 compliant implementations.
3. Use of the Registry
 SIP header field parameters and parameter values MUST be documented
 in an RFC in order to be registered by IANA. This documentation MUST
 fully explain the syntax, intended usage and semantics of the
 parameter or parameter value. The intent of this requirement is to
 assure interoperability between independent implementations, and to
 prevent accidental namespace collisions between implementations of
 dissimilar features.
 Note that this registry, unlike other protocol registries, only
 deals with parameters and parameter values defined in RFCs (i.e.,
 it lacks a vendor-extension tree). RFC 3427 [4] documents concerns
 with regards to new SIP extensions which may be damaging towards
 security, greatly increase the complexity of the protocol, or
 both. New parameters and parameter values need to be documented in
 RFCs as a result of these concerns.
 RFCs defining SIP header field parameters or parameter values MUST
 register them with IANA as described below.
 Registered SIP header field parameters and parameter values are to be
 considered "reserved words". In order to preserve interoperability,
 registered parameters and parameter values MUST be used in a manner
 consistent with that described in their defining RFC. Implementations
 MUST NOT utilize "private" or "locally defined" SIP header field
 parameters or parameter values that conflict with registered
 parameters.
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 Note that although unregistered SIP header field parameters and
 parameter values may be used in implementations, developers are
 cautioned that usage of such parameters is risky. New SIP header
 field parameters and parameter values may be registered at any
 time, and there is no assurance that these new registered
 parameters or parameter values will not conflict with unregistered
 parameters currently in use.
 Some SIP header field parameters only accept a set of predefined
 parameter values. For example, a parameter indicating the transport
 protocol in use may only accept as valid values the predefined tokens
 TCP, UDP, and SCTP. Registering all parameter values for all SIP
 header field parameters of this type would require a large number of
 subregistries. Instead, we have chosen to register parameter values
 by reference. That is, the entry in the parameter registry for a
 given header field parameter contains references to the RFCs defining
 new values of the parameter. References to RFCs defining parameter
 values appear in brackets in the registry.
 So, the header field parameter registry contains a column that
 indicates whether or not each parameter only accepts a set of
 predefined values. Implementers of parameters with a "yes" in that
 column need to find all the valid parameter values in the RFCs
 provided as references.
4. IANA Considerations
 Section 27 of RFC 3261 [3] creates an IANA registry for method names,
 header field names, warning codes, status codes, and option tags.
 This specification instructs the IANA to create a new sub-registry
 for header field parameters under
 http://www.iana.org/assignments/sip-parameters:
4.1 Header Field Parameters Sub-Registry
 The majority of the SIP header fields can be extended by defining new
 parameters. New SIP header field parameters are registered by the
 IANA. When registering a new parameter for a header field or a new
 value for a parameter, the following information MUST be provided.
 o Header field in which the parameter can appear.
 o Name of the header field parameter being registered.
 o Whether the parameter only accepts a set of predefined values.
 o A reference to the RFC where the parameter is defined and to any
 RFC that defines new values for the parameter. References to RFCs
 defining parameter values appear in brackets in the registry.
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 Parameters that can appear in different header fields MAY have the
 same name. However, parameters that can appear in the same header
 field MUST have different names.
 The following are the initial values for this sub-registry.
 Header Field Parameter Name Predefined Reference
 Values
 ___________________________________________________________
 Accept q No RFC 3261
 Accept-Encoding q No RFC 3261
 Accept-Language q No RFC 3261
 Authorization algorithm Yes RFC 3261
 [RFC 3310]
 Authorization auts No RFC 3310
 Authorization cnonce No RFC 3261
 Authorization nc No RFC 3261
 Authorization nonce No RFC 3261
 Authorization opaque No RFC 3261
 Authorization qop Yes RFC 3261
 Authorization realm No RFC 3261
 Authorization response No RFC 3261
 Authorization uri No RFC 3261
 Authorization username No RFC 3261
 Authentication-Info cnonce No RFC 3261
 Authentication-Info nc No RFC 3261
 Authentication-Info nextnonce No RFC 3261
 Authentication-Info qop Yes RFC 3261
 Authentication-Info rspauth No RFC 3261
 Call-Info purpose Yes RFC 3261
 Contact expires No RFC 3261
 Contact q No RFC 3261
 Content-Disposition handling Yes RFC 3261
 Event id No RFC 3265
 From tag No RFC 3261
 P-Access-Network-Info cgi-3gpp No RFC 3455
 P-Access-Network-Info utran-cell-id-3gpp No RFC 3455
 P-Charging-Function-Addresses ccf No RFC 3455
 P-Charging-Function-Addresses ecf No RFC 3455
 P-Charging-Vector icid-value No RFC 3455
 P-Charging-Vector icid-generated-at No RFC 3455
 P-Charging-Vector orig-ioi No RFC 3455
 P-Charging-Vector term-ioi No RFC 3455
 P-DCS-Billing-Info called No RFC 3603
 P-DCS-Billing-Info calling No RFC 3603
 P-DCS-Billing-Info charge No RFC 3603
 P-DCS-Billing-Info locroute No RFC 3603
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 P-DCS-Billing-Info rksgroup No RFC 3603
 P-DCS-Billing-Info routing No RFC 3603
 P-DCS-LAES content No RFC 3603
 P-DCS-LAES key No RFC 3603
 P-DCS-Redirect count No RFC 3603
 P-DCS-Redirect redirector-uri No RFC 3603
 Proxy-Authenticate algorithm Yes RFC 3261
 [RFC 3310]
 Proxy-Authenticate domain No RFC 3261
 Proxy-Authenticate nonce No RFC 3261
 Proxy-Authenticate opaque No RFC 3261
 Proxy-Authenticate qop Yes RFC 3261
 Proxy-Authenticate realm No RFC 3261
 Proxy-Authenticate stale Yes RFC 3261
 Proxy-Authorization algorithm Yes RFC 3261
 [RFC 3310]
 Proxy-Authorization auts No RFC 3310
 Proxy-Authorization cnonce No RFC 3261
 Proxy-Authorization nc No RFC 3261
 Proxy-Authorization nonce No RFC 3261
 Proxy-Authorization opaque No RFC 3261
 Proxy-Authorization qop Yes RFC 3261
 Proxy-Authorization realm No RFC 3261
 Proxy-Authorization response No RFC 3261
 Proxy-Authorization uri No RFC 3261
 Proxy-Authorization username No RFC 3261
 Reason cause Yes RFC 3326
 Reason text No RFC 3326
 Retry-After duration No RFC 3261
 Security-Client alg Yes RFC 3329
 Security-Client ealg Yes RFC 3329
 Security-Client d-alg Yes RFC 3329
 Security-Client d-qop Yes RFC 3329
 Security-Client d-ver No RFC 3329
 Security-Client mod Yes RFC 3329
 Security-Client port1 No RFC 3329
 Security-Client port2 No RFC 3329
 Security-Client prot Yes RFC 3329
 Security-Client q No RFC 3329
 Security-Client spi No RFC 3329
 Security-Server alg Yes RFC 3329
 Security-Server ealg Yes RFC 3329
 Security-Server d-alg Yes RFC 3329
 Security-Server d-qop Yes RFC 3329
 Security-Server d-ver No RFC 3329
 Security-Server mod Yes RFC 3329
 Security-Server port1 No RFC 3329
 Security-Server port2 No RFC 3329
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 Security-Server prot Yes RFC 3329
 Security-Server q No RFC 3329
 Security-Server spi No RFC 3329
 Security-Verify alg Yes RFC 3329
 Security-Verify ealg Yes RFC 3329
 Security-Verify d-alg Yes RFC 3329
 Security-Verify d-qop Yes RFC 3329
 Security-Verify d-ver No RFC 3329
 Security-Verify mod Yes RFC 3329
 Security-Verify port1 No RFC 3329
 Security-Verify port2 No RFC 3329
 Security-Verify prot Yes RFC 3329
 Security-Verify q No RFC 3329
 Security-Verify spi No RFC 3329
 Subscription-State expires No RFC 3265
 Subscription-State reason Yes RFC 3265
 Subscription-State retry-after No RFC 3265
 To tag No RFC 3261
 Via branch No RFC 3261
 Via comp Yes RFC 3486
 Via maddr No RFC 3261
 Via received No RFC 3261
 Via rport No RFC 3581
 Via ttl No RFC 3261
 WWW-Authenticate algorithm Yes RFC 3261
 [RFC 3310]
 WWW-Authenticate domain Yes RFC 3261
 WWW-Authenticate nonce No RFC 3261
 WWW-Authenticate opaque No RFC 3261
 WWW-Authenticate qop Yes RFC 3261
 WWW-Authenticate realm No RFC 3261
 WWW-Authenticate stale Yes RFC 3261
4.2 Registration Policy for SIP Header Field Parameters
 As per the terminology in RFC 2434 [2], the registration policy for
 SIP header field parameters and parameter values shall be
 "Specification Required".
 For the purposes of this registry, the parameter or the parameter
 value for which IANA registration is requested MUST be defined by an
 RFC. There is no requirement that this RFC be standards-track.
5. Security Considerations
 There are no security considerations associated to this document.
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6. Acknowledgements
 Jonathan Rosenberg, Henning Schulzrinne, Rohan Mahy, Dean Willis, Aki
 Niemi, Bill Marshall, Miguel A. Garcia-Martin, Jean Francois Mule,
 and Allison Mankin provided useful comments.
7 Normative References
 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
 Levels", BCP 14, RFC 2119, March 1997.
 [2] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
 Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
 [3] 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.
 [4] Mankin, A., Bradner, S., Mahy, R., Willis, D., Ott, J. and B.
 Rosen, "Change Process for the Session Initiation Protocol
 (SIP)", BCP 67, RFC 3427, December 2002.
Author's Address
 Gonzalo Camarillo
 Ericsson
 Hirsalantie 11
 Jorvas 02420
 Finland
 EMail: Gonzalo.Camarillo@ericsson.com
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