US Patent 9392436 Method and apparatus for voice over LTE

According to at least one example embodiment, a transit network is configured to handle signaling messages between service provider networks. Upon receiving, at the transit network, a session control message from a mobile network, a signaling type associated with the session control message is determined. The transit network then routes the session control message based on the signaling type determined. According to at least one aspect, the session control message is routed based on domain routing if the determined signaling type is roaming signaling. According to at least one other aspect, the session control message is routed based on called party number routing if the determined signaling type is non-roaming signaling.