switched data network

In traditional way, voice service and data service are provided independently by two different networks-PSTN ( Public Switched Telephone Network) and data communication network.

在传统方式下，话音业务和数据业务是由两个互相独立的网络&公共电话交换网（PSTN）和数据通信网分别提供的。

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VoIP is a breakthrough technology for network communications, it is based on Packet-Switched Network, its signal protocol and real-time data travels over the internet. Thus, it can be easily attacked.

VoIP是指在IP数据网络上提供通话服务，由于VoIP承载于分组交换网络，其信令协议和实时数据在Internet上传播，它继承了网络易受攻击的缺点。

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The next improvement of MSTP is to add an Automatically Switched Optical Network ( ASON) control plane and the bandwidth should be well assigned for the transport plane and control plane to support data services.

MSTP的进一步发展是加载自动交换光网络（ASON）控制平面，但要注意在支持数据业务的情况下，传送平面和控制平面在带宽调整方面的协调性；

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In data communication, the connection through the public switched telephone network from a terminal to a service, network or computer.

数据通信中，通过公共电话交换网，实现一个终端和一个服务部门、网络或计算机的连接。

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Connection to a data communications network through a public switched telecommunication network.

通过公用交换电信网连接到数据通信网络.

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