Abstract: A gateway connects to a communication device, and communicates with a voice communication server through a network. When the communication device requests to establish a voice communication with a third-party communication terminal, the gateway parses the request to calculate a network bandwidth sufficient to establish the voice communication, and then requests the voice communication server to allocate the required network bandwidth for establishing the voice communication. Then voice data streaming sent from the communication device and the third-party communication terminal are respectively processed to generate RTP packets. The RTP packets are transmitted between the communication device and the third-party communication terminal, so as to realize the voice communication between the communication device and third-party communication terminal.

Abstract: A network device for establishing quality of service (QoS) between two terminal devices includes a transceiver module and a state-machine setting module. The transceiver module is configured for receiving establishing requests, request responses, acknowledge messages, and QoS requests from any one of the two terminal devices. The state-machine setting module is configured for setting a state of the network device according to a current state of the network device and messages received by the transceiver module, and the state of the network device includes an idle state, an inviting state, a trying state, an acknowledge state, and a QoS state.

Abstract: A network device for establishing quality of service (QoS) between two terminal devices includes a transceiver module and a state-machine setting module. The transceiver module is configured for receiving establishing requests, request responses, acknowledge messages, and QoS requests from any one of the two terminal devices. The state-machine setting module is configured for setting a state of the network device according to a current state of the network device and messages received by the transceiver module, and the state of the network device includes an idle state, an inviting state, a trying state, an acknowledge state, and a QoS state.