A method of establishing a reduced setup time session through a gateway includes receiving a first capability message transmitted from the first terminal to the gateway and receiving a second capability message transmitted from the second terminal to the gateway. The method also includes processing the first capability message and the second capability message to form a third capability message and a fourth capability message. The method further includes transmitting a third capability message from the gateway to the first terminal and transmitting a fourth capability message from the gateway to the second terminal. Moreover, the method includes receiving a first request message transmitted from the second terminal to the gateway and transmitting a second request message from the gateway to the first terminal. Transmitting the second request message is performed independent of receiving the first request message. Additionally, the method includes receiving a first response message transmitted from the second terminal to the gateway and transmitting a second response message from the gateway to the first terminal. Transmitting the second response message is performed in response to receiving the first response message.