A telecommunications system includes a plurality of network clients (150)
including a positioning controller (504) and a communications controller
(502); and a positioning server (152) including a coordinating controller
(161) for maintaining a database of network clients to be tracked and
provide updates of position-related information to a presence server
(104). The plurality of network clients (150) are configured to transmit
position information received via the positioning controller (504) to the
positioning server via the communications controller (502), the
positioning information including information related to loss of a
position signal.