服务质量(QoS)是( )。

A:保证信元速率 B:保证信元延迟 C:保证突发容限 D:保证服务水平

服务质量(QOS)是________。

A:保证信元速率 B:保证信元延迟 C:保证突发容限 D:保证服务水平

QoS中IntServ模型是指（ ）

A:基于流的 QoS技术 B:基于类的 QoS技术 C:基于VLAN的QoS技术 D:基于tcont的QoS技术

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. If a mobile user wants to move from one network to another with continuous service, the terminals have to cope with network change to maintain service seamlessly. Quality of service is a major issue that the end users should be provided with the satisfying service, while the network workload and cost should not too much increased. In addition, since end users are provided with numerous service ranging from Voice-over-IP to Video-on-Demand services, it is expected that users can experience the same quality for all the different service. Therefore, the network architecture need to be designed in such a way that the quality mechanism is incorporated so that users are served according to their individual QoS requirements. Based on the paragraph above 。

To satisfy the users QoS requirements, the network architecture design should include (　).

A:Voice -over -IP B:the quality mechanism C:workload D:Video-on-Demand