Abstract: A network address translation method includes: configuring a network address translator (NAT) to receive a first control signal from a first user end indicating an intent to conduct media streaming, a media description in the first control signal including a private first address and a private first port; configuring the NAT to modify the first address and the first port to a public second address and a public second port, and to send a second control signal containing a media description that includes the second address and the second port to a control signal server; and configuring the NAT to receive a third control signal sent in response from a second user end via the control signal server, parse a media description in the third control signal to obtain a public third address and a public third port, and establish an address translation rule using the addresses and ports.

Abstract: A control device, which is for use during multimedia streaming between a user terminal and a base station over a wireless broadband network, includes a parsing unit, a computing unit and a processing unit. The parsing unit parses a session signal for establishing a multimedia streaming session so as to acquire a call ID and a media descriptor of the multimedia streaming session. The computing unit receives the media descriptor thus acquired by the parsing unit, and computes a bandwidth needed for the multimedia streaming session based on the media descriptor. The processing unit receives the call ID and the bandwidth, and transmits a quality-of-service request signal to the base station according to the bandwidth and corresponding to the multimedia streaming session so as to request the base station to provide a quality of service corresponding to the bandwidth during the multimedia streaming session.