If temporary system errors, network failures, or service unavailability occur, the data used in preparation of the call is lost.
如果出现临时系统错误、网络故障或服务不可用，准备调用过程中使用的数据将丢失。
The unavailability of a service group is based on this kind of situations that are associated with the front-end services of the service group.
服务组的不可用性正是基于这类场景，这与服务组的前端服务有关。
VOD service quality can, as for telephony, be expressed in terms of blocking or service unavailability.
视频点播服务质量可参照话音服务，按信号阻塞或服务无效性来表示。
应用推荐