15. The ____ address uniquely defines a host on the Internet.

16. The _ layer coordinates the functions required to transmit a bit stream over a physical medium.

17. The _ layer is responsible for the source-to-destination delivery of a packet across multiple network links.

18. Mail services are available to network users through the _ layer.

19. The __ created a model called the Open Systems Interconnection, which allows diverse systems to communicate.

20. The __ layer changes bits into electromagnetic signals.

21. IPv6 has __ -bit addresses.

22. The __ address identifies a process on a host.

23. The __ layer is responsible for the delivery of a message from one process to another.

24. The __ layer enables the users to access the network.

25. The TCP/IP __ layer is equivalent to the combined session, presentation, and application layers of the OSI model.

26. When a host on network A sends a message to a host on network B, which address does the router look at?

27. As the data packet moves from the upper to the lower layers, headers are __.

28. The physical layer is concerned with the movement of __ over the physical medium.

29. To deliver a message to the correct application program running on a host, the __ address must be consulted.

30. Ethernet uses a __ physical address that is imprinted on the network interface card (NIC).

31. The _ layer is the layer closest to the transmission medium.

32. The OSI model consists of _ layers.

33. The _ address, also known as the link address, is the address of a node as defined by its LAN or WAN.

34. Layer 2 lies between the physical layer and the _ layer.

35. Why was the OSI model developed?