The Mobilis Presence Server (M-PAS) provides the ability for the service provider to offer information resources for person and terminal availability, communication preferences, terminal capabilities, current activity, location, available services etc. These are provided over industry standard SIP protocol with extensions being available conformant with RFC 3455.

A user's presence information may be obtained through input from the user, information supplied by network entities or information supplied by elements external to the home network. Consumers of presence information, watchers, may be internal or external to the home network.