As such, two aspects need to be considered; the ability of a network toprovide an assured service level, and how satisfied the end user is with the service, interms of usability, accessibility, retain-ability and integrity of the service.

• 因此,要考虑两个方面:一个是网络能够提供保证服务的能力,另外就是使服务如何满足终端用户,可用性,易用性,持久性和完整性用来衡量服务的质量。