单项选择题
A. when a packet is received from an 802.1Q trunk,the vlan id can be determined from the source MAC address table.
B. unkown unicast frames are retransmitted only to the ports that belong to the same vlan
C. ports between switches should be configured in access mode so that vlans can span across the ports
D. broadcast and multicast frames are retransmitted to ports that are configured on different vlan.
单项选择题 A router receives information about network 192.168.10.0/24 from multiple sources.What will the router consider the most reliable information about the path to that network?（）
单项选择题 A receiving host computes the checksum on a frame and determines that the frame is damaged.The frame is then discarded.At which OSI layer did this happen?（）
单项选择题 Given an IP address 172.16.28.252 with a subnet mask of 255.255.240.0, what is the correct network addres?（）