At which layers of the OSI model do WANs operate? (Choose two.)（）
At which layers of the OSI model do WANs operate?（）
One of your customers has deployed a Layer 3 gateway in the untrusted network. Which gateway mode is appropriate for this customer?（）
Which of the protocols below use TCP at the transport layer?（）
Data transfer is slow between the source and destination. The quality of service requested by the transport layer in the OSI reference model is not being maintained. To fix this issue, at which layer should the troubleshooting process begin?（）
At which layers of the OSI model do WANs operate (Choose two.)（）。
A computer is connected to the network through a NIC， which has a unique assignment that is called the Ethernet MAC address. Which layer of the OSI model does the MAC address use to communicate with the network？（）
One of your customers has deployed a Layer 3 gateway in the untrusted network. Which gateway mode is appropriate for this customer？（）
At which layer of the OSI model does the Spanning Tree Protocol （STP） operate at？（）
A receiving host computes the checksum on a frame and determines that the frame is damaged.Theframe is then discarded.At which OSI layer did this happen？（）
One of your customers wishes to use the NAS to perform DHCP functions and does not currently have a Layer 3 gateway in its production network. Which gateway mode is appropriate for this customer?（）
Refer to the exhibit. An administrator pings the default gateway at 10.10.10.1 and sees the output as shown. At which OSI layer is the problem?（）https://assets.asklib.com/images/image2/2018072409560147847.jpg
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? （）
Which of the following layers of the TCP/IP model most closely corresponds to the network layer of the OSI model?（）
Which layer of the OSI reference model is responsible for ensuring reliable end-to-end delivery of data?（）
Which of the following are associated with the application layer of the OSI model？（two.）（）
Which three statements about classification marking of traffic at Layer 2 are true？ （）
At which OSI layer is a logical path created between two host systems（）。
Refer to the exhibit. At the end of an RSTP election process, which access layer switch port will assume the discarding role?（）https://assets.asklib.com/images/image2/2018072317314615527.jpg
Which of the following are associated with the application layer of the OSI model (Choose two.)（）。
At which OSI layer is a logical path created between two host systems?（）
At which layer of the OSI model is RSTP used to prevent loops？（）
Under __________, the consignment will at least be carried by two different modes of transport before it arrives at the port of destination.
One of the following network devices that works at the physical layer is（）
