Exam Essentials

Remember the DOD Model and its layers. The TCP/IP DOD model defines four layers: the Process/Application layer, the Host-to-Host layer, the Internet layer, and the Network Access layer.

Understand the function and purpose of the Process/Application layer protocols. Telnet is used for remote terminal emulation, FTP allows file transfer, SMTP is used to move mail, LPD is used for sharing printers, and X Window allows for GUI applications on client/server networks.

Understand the function and purpose of the Host-to-Host layer protocols. TCP is a connection-oriented, guaranteed, transport protocol, and it requires virtual circuits from end-to-end for data delivery. UDP is a connectionless, non-guaranteed, transport protocol and does not require end-to-end circuits for data delivery.

Understand the function and purpose of Internet layer protocols. IP provides for the logical addressing and is used by hosts and routers to locate networks and clients. ARP is used to resolve an IP address to a MAC address or to resolve logical-to-physical addressing of network devices. RARP is used by diskless workstations to map their MAC addresses to their IP addresses as assigned by the RARP server for a given session.

Understand the function and purpose of the Network layer. MAC addresses are used by each and every device connected to the network and are defined by a vendor code and serial number. Frames are converted to bits, media access methods are chosen, and electrical signaling is used to place data on the wire at the Network layer.

Remember the Novell IPX Protocol suite and its protocols and functions. IPX is a connectionless, non-guaranteed delivery protocol for logical device addressing. SPX is a connection-oriented, guaranteed delivery protocol using virtual circuits. RIP is a distance-vector routing protocol using ticks and hops as a metric. SAP is used to advertise and request services by servers and clients. NLSP is an advanced link-state routing protocol. NCP provides clients with access to network servers’ services such as file and print.