Patent ID: 7246166

Claim:
A method of enabling the establishment of a communications path between a first entity and a second entity in a communications network comprising at least two address domains, said address domains being connected by two or more network address translators, said method comprising the steps of: i) sending a call set-up message from the first entity to a first one of the network address translators via only a first one of the address domains, said call set-up message containing an address of the first entity within the first address domain; ii) receiving the call set-up message at the first network address translator and retaining the address of the first entity in the call set-up message as well as adding information indicating the identity of the first address domain to the call set-up message; iii) forwarding the call set-up message with said added information to the second entity via a second one of the address domains and a second one of the network address translators, such that the information in the call set-up message can be used to establish a communications path from the second entity to the first entity which excludes a second one of the address domains when it is determined, using the added information, that the second entity is within the first address domain.