Accounting system in a network

A data network coupled to a foreign network that includes a base station with an access hub and a foreign mobile switching center with a serving registration server, the access hub including a serving inter-working function, the serving inter-working function including a serving accounting collection module, the data network comprising:

• a home network that includes a home mobile switching center with a home inter-working function, the home inter-working function including a home accounting collection module;
• and
• an end system subscribed to the home network and coupleable to the foreign access hub, the home and serving accounting collection-modules collecting accounting data on message traffic transported between the end system and a communications server through the home inter-working function and through the serving inter-working function.

A home network for use in a data network coupled to a foreign network that includes a base station with an access hub and a foreign mobile switching center with a serving registration server, the access hub including a serving inter-working function, the serving inter-working function including a serving accounting collection module, and an end system subscribed to the home network and coupleable to a foreign access hub, the home network comprising:

• a home mobile switching center with a home inter-working function, the home inter-working function including a home accounting collection module;
• and
• wherein the home and serving accounting collection modules collecting accounting data on message traffic transported between the end system and a communications server through the home inter-working function and through the serving inter-working function.

A foreign network for use in a data network coupled to a home network that includes a home mobile switching center with a home inter-working function, the home inter-working function including a home accounting collection module, and an end system subscribed to the home network and coupleable to a foreign access hub, the foreign network comprising:

• a base station with an access hub, the access hub including a serving inter-working function, the serving inter-working function including a serving accounting collection module;
• a foreign mobile switching center with a serving registration server;
• wherein the home and serving accounting collection modules collecting accounting data on message traffic transported between the end system and a communications server through the home inter-working function and through the serving inter-working function.

An end system for use in a data network coupled to a foreign network that includes a base station with an access hub and a foreign mobile switching center with a serving registration server, the access hub including a serving inter-working function, the serving inter-working function including a serving accounting collection module, a home network including a home registration server and a plurality of unassigned home inter-working functions and a home accounting collection module, the end system comprising:

• the end system being subscribed to the home network and coupleable to the foreign access hub, the home and serving accounting collection modules collecting accounting data on message traffic transported between the end system and a communications server through the home inter-working function and through the serving inter-working function.