问题
单项选择题
In low-speed network, it is usually adequate to wait for congestion to occur and then react to it by telling the source of packets to slow down. In high-speed networks, this approach often works poorly, because in the ______ between sending the notification and notification arriving at the source, thousands of additional ______ may arrive. In ATM network, a major tool for preventing ______ is ______ control. When a host wants a new virtual ______, it must describe the traffic to be offered and the service expected.
A．interval
B．time
C．slot
D．delay
答案
参考答案：A
解析： 在低速网络中，通常采用碰到拥塞时，通过向源端反映使其降低发送速率。而在高速网络中，这种方式将会恶化，因为在发送通告和通告到达之间会有成千上万的其他数据包到达。在ATM网络中，主要采用允许控制来避免拥塞，当有一台主机要建立一条新的虚连接时，它必须描述它所需的流量和服务等级。