传统长途电话网向分组化网络的演进之路──BICC

An Evolution Road from Traditional Toll Network to Packetized Network──BICC

传统ＰＳＴＮ网向分组化网络演进是历史的必然，而长途电话网的演进则是首当其冲。本文首 先分析了这种演进的必然性及演进中遇到的问题，指出承载无关的呼叫控制（ＢＩＣＣ）为此铺 就了既面向未来又能充分地利用已有承载网投资的演进之路。接着本文介绍了ＢＩＣＣ的功能和 协议模型，以及ＢＩＣＣ在信令消息及信令处理过程方面与ＩＳＵＰ的差别，并用一个例子说明 了ＢＩＣＣ的动态流程。最后本文还介绍了ＢＩＣＣ协议标准化的现状和未来。

It is inevitable to evolve from PSTN toward ATM/IP dominated packetized network, this evolution will first start with traditional toll network. This paper present the reason of this evolution and the problems emerged in current solutions. As a alternative evolution road. the paper points out the Bearer Independent Call Control-BICC is future-oriented and can reuse the investment oil existing bearer network effectively. Then. this paper introduces the network functional and protocol model of BICC and explains the exceptions to ISUP on signalling messages and procedures sides. For a better understanding, this paper illustrates the flow of BICC. Finally, the paper introduces the current situation and the future of BICC standardization.