POP
Point of Presence. A long‐distance carrier's office in a community (defined as local LATA). A POP is the place a long‐ distance carrier, called an...
Definition:
Presence, or presence information, conveys the ability and willingness of a user to communicate with other users on a
network, across a set of devices. IETF RFC 2778 defines a model and terminology for describing systems that provide
presence information. In that model a presence service is a system that accepts, stores, and distributes presence
information to interested parties.