Patent ID: 8559411

Claim:
A communications method for use in a communications system including a first network address domain, a second network address domain, and an intermediate node, said intermediate node including first and second interfaces, said first interface having a first network address routable in the first network address domain, said second interface having a second network address routable in said second network address domain, said first and second network address domains being different, said system further including a downstream node and an upstream node, said downstream node having an interface and a network address in the first network address domain, said upstream node having an interface and a network address in the second network address domain, the method comprising the steps of: operating the upstream node to receive a second message including a second message body and a second header, said second message body including at least one instruction from said downstream node and said second network address corresponding to said second interface, said second header including a destination address corresponding to said upstream node, said at least one instruction having been received by said intermediate node in a first message from said downstream node, and said at least one instruction being an instruction for invoking a process between the upstream node and the intermediate node, wherein said second message includes an intermediate node downstream address that was dynamically allocated at the downstream node; and operating the upstream node to use said second network address in a tunnel establishment operation implemented in accordance with said at least one instruction, wherein said at least one instruction is an instruction to send a third messages, said third message including the intermediate node downstream address that was dynamically allocated at the downstream node and an intermediate node upstream address which was generated at the intermediate node.