单项选择题
1000BaseT has a MAXIMUM run distance of:（）
A. 25 meters (82 feet) B. 100 meters (328 feet) C. 500 meters (1640 feet) D. 1000 meters (3280 feet)
单项选择题 Which of the following features is essential in a firewall if it is to support RTP sessions?（）
单项选择题 A layer 3 switch can move packets between subnets based on which of the following criteria?（）
单项选择题 Which of the following is an invalid IPv4 address?（）
