Registering a SIP Resource Priority Header Field Namespace for Local Emergency Communications
RFC 7135

Internet Engineering Task Force (IETF)                           J. Polk
Request for Comments: 7135                                 Cisco Systems
Category: Informational                                         May 2014
ISSN: 2070-1721

     Registering a SIP Resource Priority Header Field Namespace for
                     Local Emergency Communications

Abstract

   This document creates the new Session Initiation Protocol (SIP)
   Resource Priority header field namespace 'esnet' and registers this
   namespace with IANA.  The new header field namespace allows for local
   emergency session establishment to a public safety answering point
   (PSAP), between PSAPs, and between a PSAP and first responders and
   their organizations.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7135.

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Polk                          Informational                     [Page 1]
RFC 7135                 Emergency RPH Namespace                May 2014

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Rules of Usage of the Resource Priority Header Field . . . . .  4
   3.  "esnet" Namespace Definition . . . . . . . . . . . . . . . . .  6
     3.1.  Namespace Definition Rules and Guidelines  . . . . . . . .  6
     3.2.  The 'esnet' Namespace  . . . . . . . . . . . . . . . . . .  6
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  7
     4.1.  IANA Resource-Priority Namespace Registration  . . . . . .  7
     4.2.  IANA Priority-Value Registrations  . . . . . . . . . . . .  7
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  8
   7.  Normative References . . . . . . . . . . . . . . . . . . . . .  9

1.  Introduction

   This document creates the new Session Initiation Protocol (SIP)
   Resource Priority header (RPH) field namespace 'esnet' for local
   emergency usage and registers this namespace with IANA.  The SIP
   Resource-Priority header field is defined in RFC 4412 [RFC4412].  The
   new 'esnet' namespace is to be used for inbound calls towards a
   public safety answering point (PSAP), between PSAPs, and between a
   PSAP and first responders or their organizations within managed IP
   networks.  This namespace is not for use on the open public Internet
   because it can be trivially forged.

   Adding an RPH with the 'esnet' namespace can be differentiated from
   the marking of an emergency call using a service URN as defined in
   [RFC5031] in that the RPH specifically requests preferential
   treatment in networks that honor it, while the marking merely
   identifies an emergency call without necessarily affecting resources
   allocated to it.  It is appropriate to use both where applicable.
   RPH with 'esnet' may also be used within public safety networks for
   SIP sessions that are not emergency calls and thus not marked per RFC
   5031.

   This new namespace is included in SIP requests to provide an explicit
   priority indication within controlled environments, such as an IP
   Multimedia Subsystem (IMS) infrastructure or Emergency Services
   network (ESInet) where misuse can be reduced to an acceptable level
   because these types of networks have controls in place.  The function
   facilitates differing treatment of emergency SIP requests according
   to local policy, or more likely, a contractual agreement between the