计算机网络分为两类:采用点到点连接的网络和采用广播信道的网络。在所有广播网络中,最关键的问题是:当信道的使用产生竞争时,如何分配信道的使用权。ADSL-非对称数字用户环路,是一种新的数据传输方式,它因为上行和下行带宽不对称,因此称为非对称数字用户环路,它采用频分复用技术把普通的电话线分成了电话、上行和下行三个相对独立的信道,从而避免了相互的干扰。 Computer networks fall into two categories: networks that use point-to-point connections and networks that use broadcast channels. In all broadcast networks, the most crucial question is how to allocate channel usage rights when the use of channels is competing. ADSL - Asymmetric Digital Subscriber Loop is a new way of data transmission. It is called an asymmetric digital subscriber loop because of its asymmetric uplink and downlink bandwidth. It divides an ordinary telephone line into The phone, uplink and downlink three relatively independent channel, thus avoiding mutual interference.