Patent ID: 8230074

Claim:
A method of reducing memory usage in first and second servers communicating in a communication network utilizing the Session Initiation Protocol (SIP), said method comprising: establishing a SIP dialogue between instances of the first and second servers to support a SIP subscription, wherein the step of establishing the SIP dialogue includes: sending a SIP Subscribe request from the first server to the second server requesting that a SIP subscription be established, said SIP Subscribe request including an indication that the first server supports SIP tunneling, if the second server also supports SIP tunneling, determining by the second server whether the second server already has an existing SIP tunnel with the first server corresponding to the SIP dialogue, if the second server already has an existing SIP tunnel with the first server corresponding to the SIP dialogue, creating a relation between the requested SIP subscription and the existing SIP tunnel, and sending a SIP response from the second server to the first server identifying the relation, and if the second server does not have an existing SIP tunnel with the first server corresponding to the SIP dialogue, sending a SIP response from the second server to the first server indicating that the second server supports SIP tunneling, wherein in response, the first server creates a SIP tunnel with the second server corresponding to the SIP dialogue for the requested SIP subscription; and utilizing the established SIP dialogue and corresponding established SIP tunnel to tunnel all SIP requests and responses within the SIP subscription between the instances of the first and second servers.