多项选择题
A. Both devices stop transmiting, wait a random period of time, verify the wire is idle, and re-transmit
B. The device with the lowest MAC address is permitted to retrannsmit first
C. The device with the lowest MAC address sends a jam signal to notify all other devices of the collision
D. Both devices send a jam signal to notify all other devices of the collision
单项选择题 You have been asked to use a 23-bit network mask to segment the network block 209.18.12.0, How many usable host address will there e per subnet?（）
单项选择题 You want to log into the router and make a configuration change.After loggin in as the root user, what is the next command you must enter?（）
单项选择题 What is the operating system do Juniper Networks MX Series routers use?（）