Patent ID: 8700706

Claim:
A method for ascertaining active communication sessions, the method comprising: receiving a request to ascertain active communication sessions by a communication session information server; transmitting respective challenges to determine whether communication sessions are currently active from the communication session information server to at least two communication session servers; receiving respective challenge responses from the at least two communication session servers, which indicate one or more active communication sessions controlled by the respective communication session server or indicate that such communication sessions currently do not exist, by the communication session information server; transmitting a first response, which indicates one or more active communication sessions controlled by the respective at least two communication session servers or indicates that such communication sessions currently do not exist, by the communication session information server; and transmitting a second response, which indicates one or more active communication sessions, controlled by the at least two communication session servers, which were not indicated in the first response, by the communication session information server; wherein the communication sessions indicated in the second response which were not indicated in the first response contain one or more communication sessions which were not active and/or did not fulfill the one or more conditions at the time of the transmissions of the first response.