Multiple-Recipient MESSAGE Requests in the Session Initiation Protocol (SIP)
RFC 5365

Network Working Group                                   M. Garcia-Martin
Request for Comments: 5365                                  G. Camarillo
Category: Standards Track                                       Ericsson
                                                            October 2008

                 Multiple-Recipient MESSAGE Requests in
                 the Session Initiation Protocol (SIP)

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 specifies a mechanism that allows a SIP User Agent
   Client (UAC) to send a SIP MESSAGE request to a set of destinations,
   by using a SIP URI-list (Uniform Resource Identifier list) service.
   The UAC sends a SIP MESSAGE request that includes the payload along
   with the URI list to the MESSAGE URI-list service, which sends a
   MESSAGE request including the payload to each of the URIs included in
   the list.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  URI-List Document  . . . . . . . . . . . . . . . . . . . . . .  5
   5.  Option-Tag . . . . . . . . . . . . . . . . . . . . . . . . . .  6
   6.  Procedures at the User Agent Client  . . . . . . . . . . . . .  6
   7.  Procedures at the MESSAGE URI-List Service . . . . . . . . . .  7
     7.1.  Determining the Intended Recipient . . . . . . . . . . . .  8
     7.2.  Creating an Outgoing MESSAGE Request . . . . . . . . . . .  8
     7.3.  Composing Bodies in the Outgoing MESSAGE Request . . . . . 10
   8.  Procedures at the UAS  . . . . . . . . . . . . . . . . . . . . 11
   9.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
   10. Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   11. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15
   13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     13.1. Normative References . . . . . . . . . . . . . . . . . . . 16
     13.2. Informative References . . . . . . . . . . . . . . . . . . 17

Garcia-Martin & Camarillo   Standards Track                     [Page 1]
RFC 5365        SIP Multiple-Recipient MESSAGE Requests     October 2008

1.  Introduction

   RFC 3261 (SIP) [RFC3261] is extended by RFC 3248 [RFC3428] to carry
   instant messages in MESSAGE requests.  SIP-based messaging, as
   described in RFC 3428 [RFC3428], does not provide a mechanism to send
   the same request to multiple recipients or replying to all recipients
   of a SIP MESSAGE request.  This memo addresses these functions.

   A first requirement can be expressed as:

      REQ-1: It must be possible for a user to send an instant message
      request to an ad hoc group, where the identities of the recipients
      are carried in the message itself.

   One possibility to fulfill the above requirement is to establish a
   session of instant messages with an instant messaging conference
   server, and exchange the messages, for example, using MSRP (Message
   Session Relay Protocol) [RFC4975].  While this option seems to be
   reasonable in many cases, in other situations the sending user just
   wants to send a small pager-mode instant message to an ad hoc group
   without the burden of setting up a session.  This document focuses on
   sending a pager-mode instant message to a number of intended
   recipients.

   To meet the requirement with a pager-mode instant message, we allow
   SIP MESSAGE requests carry recipient-list bodies, i.e., URI lists in
   body parts whose Content-Disposition (RFC 2183) [RFC2183] is
   'recipient-list', as specified in RFC 5363 [RFC5363].  A SIP MESSAGE
   URI-list service, which is a specialized application service,
   receives the request and sends a MESSAGE request including the
   received payload to each of the URIs in the list.  Each of these
   MESSAGE requests contains a copy of the body included in the original
   MESSAGE request.

   A second requirement addresses the "Reply-To-All" functionality:

      REQ-2: It MUST be possible for the recipient of a group instant
      message to send a message to all other participants that received
      the same group instant message (i.e., Reply-To-All).

   To meet this requirement, we provide a mechanism whereby the MESSAGE
   URI-list service also includes a URI list in body parts whose