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作为80年代开始逐步商用化的数字数据网(DDN)是一种介于永久性连接和交换式连接之间的利用数字通道提供半永久性连接电路,以传输数据信号为主的数字传输网络。它主要提供中、高速率高质量点到点和点到多点的数字专用电路。其线路的通令速率2.4-19.2KB/S、N*64KB/S(N=1-32)。当前,我国一些地区的 DDN 网上配置端口和通过在帧中继中 X.25上更新软件实现帧中继业务以及8KB/S、16KB/S、32KB/S 压
Digital Data Network (DDN), which began to be commercialized gradually in the 1980s, is a digital transmission network that uses digital channels to provide semi-permanent connection between the permanent connections and the switched connections to transmit data signals. It mainly provides digital high-speed, high-quality point-to-point and multipoint digital circuits. The order speed of its line is 2.4-19.2KB / S, N * 64KB / S (N = 1-32). At present, the DDN network in some areas of our country configures the port and realizes the frame relay business and the 8KB / S, 16KB / S, 32KB / S presses through the renewal software on the frame relay in X.25