US Patent 7113504 Advanced voice communication feature transparency in a telecommunications network

An auxiliary communication network is introduced into a virtual private network for passing signaling messages that present features not supported by the public, primary communication network portion of the virtual private network. Protocol converters are positioned within the virtual private network to intercept signaling messages, establish a connection through the auxiliary network, determine whether the intercepted messages present unsupported features, and, in which case, route corresponding feature requested through the auxiliary communication network. Preferably, the auxiliary network connection is established in a direction reverse to and in response to the primary network connection.