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A network administrator is verifying the configuration of a newly installed host by establishing an FTP connection to a remote server. What is the highest layer of the protocol stack that the nework administrator is using for this operation?（）

A. application
B. presentation
C. session
D. transport
E. internet
F. data link

单项选择题Refer to the exhibit, Host A pings interface S0 0 on router 3, what is the TTL value for that ping?（）

A. 253
B. 252
C. 255
D. 254

单项选择题Which layer in the OSI reference model is responsible for determining the availability of the receiving program and checking to see if enough resources exist for that communication?（）

A.transport
B.network
C.presentation
D.session
E.application

多项选择题Refer to the exhibit. Which three statements correctly describe Network Device A（）

A.With a network wide mask of 255.255.255.128, each interface does not require an IP address.
B.With a network wide mask of 255.255.255.128, each interface does require an IP address on a unique IP subnet.
C.With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other.
D.With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other.
E.With a network wide mask of 255.255.254.0, each interface does not require an IP address.

多项选择题Refer to the exhibit. What will Router1 do when it receives the data frame shown?（）

A.Router1 will strip off the source MAC address and replace it with the MAC address 0000.0c36.6965.
B.Router1 will strip off the source IP address and replace it with the IP address 192.168.40.1.
C.Router1 will strip off the destination MAC address and replace it with the MAC address 0000.0c07.4320.
D. Router1 will strip off the destination IP address and replace it with the IP address of 192.168.40.1.
E.Router1 will forward the data packet out interface FastEthernet0/1.
F.Router1 will forward the data packet out interface FastEthernet0/2.