RFC 3343 (rfc3343) - Page 2 of 23

The Application Exchange (APEX) Presence Service

RFC 3343        The Application Exchange (APEX) Presence      April 2003


       Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 22
       Full Copyright Statement . . . . . . . . . . . . . . . . . . . 23

1. Introduction

   This memo describes a presence service that is built upon the APEX
   [1] "relaying mesh".  The APEX presence service is used to manage
   presence information for APEX endpoints.

   APEX, at its core, provides a best-effort datagram service.  Within
   an administrative domain, all relays must be able to handle messages
   for any endpoint within that domain.  APEX services are logically
   defined as endpoints, but given their ubiquitous semantics they do
   not necessarily need to be associated with a single physical
   endpoint.  As such, they may be provisioned co-resident with each
   relay within an administrative domain, even though they are logically
   provided on top of the relaying mesh, i.e.,

      +----------+     +----------+    +----------+    +---------+
      |   APEX   |     |   APEX   |    |   APEX   |    |         |
      |  access  |     | presence |    |  report  |    |   ...   |
      | service  |     |  service |    | service  |    |         |
      +----------+     +----------+    +----------+    +---------+
           |                |               |               |
           |                |               |               |
   +----------------------------------------------------------------+
   |                                                                |
   |                            APEX core                           |
   |                                                                |
   +----------------------------------------------------------------+

   That is, applications communicate with an APEX service by exchanging
   data with a "well-known endpoint" (WKE).

   APEX applications communicate with the presence service by exchanging
   data with the well-known endpoint "apex=presence" in the
   corresponding administrative domain, e.g.,
   "apex=" is the endpoint associated with the
   presence service in the "example.com" administrative domain.

   Note that within a single administrative domain, the presence service
   makes use of the APEX access [3] service in order to determine if an
   originator is allowed to view or manage presence information.







Rose, et al.                  Experimental