RFC 3343 (rfc3343) - Page 2 of 23
The Application Exchange (APEX) Presence Service
Alternative Format: Original Text Document
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