| The following sections provide you with the opportunity to review what you learned in this chapter and to test yourself. The Facts The application layer provides access to the network for applications and certain user functions. Displays incoming information and prepares outgoing information for network access. The presentation layer converts data from the application layer into a format that can be sent over the network. Converts data from the session layer into a format that can be understood by the application layer. Handles encryption and decryption of data. Provides compression and decompression functionality. The session layer synchronizes the data exchange between applications on separate devices. Handles error detection and notification to the peer layer on the other device. The transport layer establishes, maintains, and breaks connections between two devices. Determines the ordering and priorities of data. Performs error checking and verification and handles retransmissions, if necessary. The network layer provides mechanisms for the routing of data between devices across single or multiple network segments. Handles the discovery of destination systems and addressing. The data-link layer has two distinct sublayers: LLC and MAC. It performs error detection and handling for the transmitted signals and defines the method by which the medium is accessed. Finally, it defines hardware addressing through the MAC sublayer. The physical layer defines the physical structure of the network. It defines voltage/signal rates and the physical connection methods as well as the physical topology. Application protocols map to the application, presentation, and session layers of the OSI model. These include AFP, FTP, TFTP, NCP, SMTP, HTTP and SNMP. Transport protocols map to the transport layer of the OSI model and are responsible for the transporting of data across the network. These include ATP, NetBEUI, SPX, TCP, and UDP. The NetBEUI protocol uses names as addresses and is not routable. Network protocols are responsible for providing the addressing and routing information. These include IP, IPX, and DDP. RIP is routing protocol. There are versions of RIP for both IPX/SPX and TCP/IP networks.
Key Terms Exam Prep Questions | 1: | Which of the following protocols provide network routing functionality? (Choose two.) A. NBP B. RIP C. RTMP D. NCP
| | 2: | Which of the following protocols uses the MAC address as part of the addressing scheme? A. IPX/SPX B. TCP/IP C. AppleTalk D. NetBEUI
| | 3: | At which OSI layer does a WAP operate? A. Network B. Physical C. Data-link D. Session
| | 4: | Which of the following are sublayers of the data-link layer? (Choose two.) A. MAC B. LCL C. Session D. LLC
| | 5: | Which of the following protocols uses names as network addresses? A. NetBEUI B. TCP/IP C. IPX/SPX D. AppleTalk
| | 6: | Which of the following characteristics best describe the SPX protocol? (Choose two.) A. Provides a connectionless communication between network devices. B. Provides connection-oriented communication between network devices. C. Functions at the network layer of the OSI model. D. Functions at the transport layer of the OSI model.
| | 7: | Which of the following OSI layers is responsible for establishing connections between two devices? A. Network B. Transport C. Session D. Data-link
| | 8: | Which of the following protocol suites uses ZIP? A. TCP/IP B. IPX/SPX C. NetBEUI D. AppleTalk
| | 9: | Which of the following protocols offer guaranteed delivery? (Choose two.) | | 10: | At which OSI layer does a switch operate? A. Layer 1 B. Layer 2 C. Layer 3 D. Layer 4
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Answers to Exam Prep Questions| A1: | The correct answers are B and C. RIP is a distance-vector routing protocol used on TCP/IP and IPX/SPX networks. RTMP is a routing protocol used on AppleTalk networks. Answer A, NBP, is incorrect. The NBP protocol is used to map computer hostnames to network layer addresses on AppleTalk networks. Answer D is incorrectNCP is a part of the IPX/SPX protocol suite that makes network services available to clients. | | A2: | The correct answer is A. IPX/SPX uses the MAC address to identify the node and network addresses. TCP/IP, answer B, uses a four octet address to identify the node and network. AppleTalk uses a 24-bit addresspart of which is randomly generated and part of which is manually assigned. NetBEUI uses alphanumeric names to refer to devices. | | A3: | The correct answer is C. A wireless access point (WAP) operates at the data-link layer of the OSI model. An example of a network layer device is a router. An example of a physical layer device is a hub. Session layer components are normally software, not hardware. | | A4: | The correct answers are A and D. The data-link layer is broken into two distinct sublayers, the Media Access Control (MAC) and the Logical Link Control (LLC). LCL is not a valid term, and session is another of the OSI model layers. | | A5: | The correct answer is A. NetBEUI uses names as network addresses. All the other network protocols listed use numbered addressing schemes at the network layer to identify systems. | | A6: | The correct answers are B and D. SPX is a connection-oriented protocol that operates at the transport layer of the OSI model. IPX is an example of a connectionless protocol. Network layer protocols are most commonly associated with route discovery and datagram delivery. | | A7: | The correct answer is B. The transport layer is responsible for establishing a connection between networked devices. The Network layer is most commonly associated with route discovery and datagram delivery. Protocols at the Session layer synchronize the data exchange between applications on separate devices. Protocols at the Data-link layer perform error detection and handling for the transmitted signals and define the method by which the medium is accessed. | | A8: | The correct answer is D. The Zone Information Protocol (ZIP) is used to divide AppleTalk network devices into logical groups called zones. None of the other protocol suites listed use ZIP or zones. TCP/IP uses network numbers to define logical areas of a network, as does IPX/SPX. NetBEUI uses workgroup names, which are similar to zones, but it does not use ZIP. | | A9: | The correct answers are A and D. Both SPX and TCP are connection-oriented protocols, which guarantee delivery of data. IPX is a connectionless transport protocol, and IP is a network layer protocol that's responsible for tasks such as addressing and route discovery. | | A10: | The correct answer is B. A switch uses the MAC addresses of connected devices to make its forwarding decisions. Therefore, it is referred to as a data-link, or Layer 2, network device. Devices or components that operate at Layer 1 are typically media based, such as cables or connectors. An example of a Layer 3 device would be a router. Layer 4 components are typically software based, not hardware. |
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