Protocols

Margaret Ducre **Protocol: **A set of rules that enable various components of the network to communicate with each other. ** 3 Examples ** 1. Network cards must know how to communicate to other Network Cards to exchange information. 2. Operating Systems must know how to communication to network cards in order to send and receive data on the network. 3. Application programs must know how to communicate to operating systems in order to know how to retrieve a file from a network server. 1. Lowest Level - what type of electronic signal represents a 1 and what type represents 0. 2. Highest Level - allows a computer user to send email to another computer user. 3. In Between Levels (7 Layers - OSI Reference Model) A. Lower Layers 1. Physical Layer a. layout of cables (type of cables and connectors used), and layout of devices that the cable is connected to. Ex: Cable: Ethernet Cable & Devices: Repeaters, Hubs, Network adapter 2. Data Link Layer a. provides a Mac address (hard-wired into every network device by the manufacturer) and is a means for data to be sent over the physical layers in the form of packets. Ex: Switches 3. Network Layer a. logical addressing a network device by you, and using a device to route network messages from one computer to another. Ex: Logical Address: IP or IPX & Routing: Router. B. Upper Layers 4. Transport a. Transport packets from one computer to another Ex: TCP (normally paired with IP), SPX (normally paired with IPX), and UDP. 5. Session a. a communication exchange of connection-oriented transmission between two networks devices. Ex: Transmission: Simplex, Half-Duplex or Full-duplex 6. Presentation a. How data is represented to applications Ex: ASCII and EBCDIC 7. Application a. Techniques that applications use to communicate with the network. Ex: DNS, FTP, SMTP, SMB, NFS, and Telnet
 * 3 Types of Protocol **