从２０世纪９０年代中期开始，因特网迅速发展，业务种类日益增多，特别是宽带业务，使数据通信业务量猛增。近年来已经达到了每９个月就要翻一番的程度，发展和速度已远远超过了电话业务的增长速度，使电信网也将向多业务数据网络的方向发展。业务的发展对网络的性能提出了高 Since the mid-1990s, the Internet has been rapidly expanding with more and more types of services, especially broadband services, causing the volume of data communications to soar. In recent years, it has reached the level of doubling every nine months. Its development and speed have far exceeded the growth rate of the telephone business, so that the telecommunications network will also move towards the multi-service data network. The development of business has raised the performance of the network