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Concluded WG SIP-TO-XMPP (stox)

Note: The data for concluded WGs is occasionally incorrect.

Acronym stox
Area Applications and Real-Time Area (art)
State Concluded
Charter charter-ietf-stox-01 Approved
Document dependencies
Additional resources Issue tracker, Wiki
Personnel Chairs Markus Isomaki, Yana Stamcheva
Area Director Ben Campbell
Mailing list Address
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Final Charter for Working Group

Problem Statement

The IETF has defined two signalling technologies that can be used
for multimedia session negotiation, instant messaging, presence,
file transfer, capabilities discovery, notifications, and other types
of real-time functionality:

o The Session Initiation Protocol (SIP), along with various SIP
extensions developed within the SIP for Instant Messaging and
Presence Leveraging Extensions (SIMPLE) Working Group.

o The Extensible Messaging and Presence Protocol (XMPP), along
with various XMPP extensions developed by the IETF as well as by
the XMPP Standards Foundation.

SIP has been focused primarily on media session negotiation (e.g.,
audio and video), whereas XMPP has been focused primarily on messaging
and presence. As a result, the technologies are mostly complementary.
However, there is also some overlap between SIP and XMPP, since there
are SIP extensions for messaging, presence, groupchat, file transfer,
etc., and there are XMPP extensions for multimedia session negotiation.
This overlap has practical implications, since some deployed services
use SIP for both media and messaging/presence, whereas other deployed
services use XMPP for both messaging/presence and media. When such
services wish to exchange information, they often need to translate
their native protocol (either SIP or XMPP) to the other protocol
(either XMPP or SIP).

Implementers needing to perform such protocol mappings have often worked
out their own heuristics for doing so. Unfortunately, these heuristics
are not always consistent, which can lead to interoperability problems.


To make it easier for implementers to enable interworking between
SIP-based systems and XMPP-based systems, several Internet-Drafts have
defined guidelines for protocol mapping between SIP and XMPP, starting
with draft-saintandre-xmpp-simple-00 in early 2004. The current
documents are:


Those documents are fairly stable and the authors have received feedback
from a number of implementers over the years. However, implementers do
not always know that such mapping specifications exist, because they are
Internet-Drafts and sometimes they have become expired due to
inactivity. Thus it would be helpful to publish a set of mapping
specifications as RFCs; the foregoing Internet-Drafts provide likely
starting points, but other proposals are welcome as per normal IETF
working group processes.

It might also be helpful to at some point publish additional documents
in the same series, covering topics like capabilities discovery and
file transfer. However, any such work would require a recharter.

The group shall not be tasked with defining any new protocols, only with
specifying mappings between existing protocols that have been defined
for SIP and XMPP.


  1. Address mapping and error handling
  2. Presence mapping
  3. Mapping for single instant messages
  4. Mapping for one-to-one text chat sessions
  5. Mapping for multi-user text chat sessions
  6. Mapping for media signaling

All of the foregoing deliverables are standards track, since they are
subject to interoperability testing.


Date Milestone Associated documents
Oct 2013 Submit mapping specifications to the IESG
Aug 2013 Start Working Group Last Call on mapping specifications
Jun 2013 Accept starting-point mapping specifications as WG items