11n is a WLAN standard approved by the (), which can be used ti support data rate uo to 600Mbps

The VoIP gateway can perform the digitization, () and encapsulation required, and it controls the setup of VoIP calls between the calling device and the called device

To maintain a telephone conversation over the Internet. The voice packets must arrive at their destination in ()

A Next Generation Network(NGN) is a () network ,which is able to provide Telecomunication Services ti users and to make use of multiple broadband, QoS-enable transport technologies and in which service-related functions are (下题选择) of the underlying transport-related technologies.

A Next Generation Network(NGN) is a (上题选择) network ,which is able to provide Telecomunication Services ti users and to make use of multiple broadband, QoS-enable transport technologies and in which service-related functions are () of the underlying transport-related technologies.

With the explosive popularity of mobile devices, we have witnessed a steady increase in demand for mobile date service. In addition mobile users also expect to connect to the Internet for communicate and access to services through the best suitable connection, anywhere and at anytime. Although the seamless roaming capability is well supported in conventional. Cellular communication networks, roaming and interworking technologies are still immature in heterogenous wireless networks. Seamless roaming over heterogenous wireless networks will be an ongoing and improved process, due to the requirements from both end users and network administrators. From the wireless access networks belonging to different administrative domains, mobile users cannot always identify at every instance which network is the best one to access for their service. It is highly demanded to establish a network architecture which can facilitate mobile terminals to access the appropriate network in a cost-effective way