多项选择题
A.protocol
B.VLAN number
C.TCP or UDP port numbers
D.source switch port number
E.source IP address and destination IP address
F.source MAC address and destination MAC address
单项选择题 Acknowldgement, Sequencing, and Flow control are characteristics of which OSI layer?（）
单项选择题 The administrator is unable to establish connectivity between two Cisco routers. Upon reviewing the command output of both routers, what is the most likely caust of the problem?（）
多项选择题 Exhibit: Which of the following are true regarding the command output shown in the display (Choose two.)（）。