|Fig : List of Protocols|
In Simple Language we can say Protocols is set of rules of internet.
Different protocols used in computer network like HTTP (Hyper Text Transfer Protocol), FTP (File Transter Protocol), TCP (Transmission Control Protocols), UDP (User Datagram Protocol), ARP (Address Resolution Protocol), DNS (Domain Name System) etc.
Service-: Service is defined as a set of operation that a layer can provide to the layer above it. It does not specify anything about the implementation of these operation.
Needs of Protocols-:1. A network protocol has to define how all the operation within a network will perform.
2. It can define how the entities outside the network will interact.
3. How data transfer from point A to point B.
4. How computer and device communication.
5. How a file is printed on a printer.
6. How a data is transmitted over a telephone line.