What are network protocols?

You are an Indian. You go to China. You meet a person and need to exchange ideas. What if you start speaking in Hindi and he in Chinese and neither of you understands the other? The attempt at communication will fail miserably. On the other hand if you both know English and agree to communicate using that language you will be able to understand each other very well indeed.

Just like you, computers too have to communicate with each other. They have rules and procedures for communicating and these are known as protocols.

There are many protocols that exist today. Protocols provide basic communications. However different protocols have different purposes and functions. They serve in the different layers of the Open System Interconnection
(OSI) model.

Functions of protocols

To transfer data, first the data is broken down into systematic steps. At each step, specific actions should take place without fail. Each step has rules and procedures governing it, which means that protocols are followed at each and every step. So the data is sent from one computer to the other and the sending and receiving computers observe the necessary protocols.

The sender and the receiver protocol

The protocol at the sending computer as well as the receiving computer has specific functions to perform.

The sending computer protocol breaks data into smaller sections. Addressing information is added to the packets so that the receiving computer will know that the data belongs to it. Now the data is made ready for transmission through the network adapter card and then onto the network cable.

Now the data has to be received. The protocol of the receiving computer carries the same procedures that the sending computer protocols did. However here it is in the reverse order. First the data packets are taken off the cable and brought into the computer through the network adapter card. The transmitting information added to the data packets by the sending computer are taken off. After this, the data is copied into a buffer for re-assembly. Finally, the reassembled data is passed to the application in a usable form.

Different types of Protocols

The different protocols in the OSI model can be broadly divided into three types. They
are: 

· Network protocols — these are rules for communicating in a particular network environment. Internet Protocol,
IPX, NetBEUI etc are examples.

· Transport protocols — they ensure that the data is properly delivered between computers. TCP (Transmission Control Protocol), ATP (AppleTalk Transaction Protocol) etc are examples.

· Application protocols — these protocols provide application-to-application interaction and data exchange. Simple Mail Transfer Protocol
(SMTP), File Transfer Protocol (FTP) etc are examples.

The most common protocols are

· TCP/IP

· IPX/SPX

· NetBIOS

. NetBEUI

· DECnet

· AppleTalk

TCP/IP

Transmission Control Protocol/Internet Protocol (TCP/IP) has today become the de facto standard for internetworking. It provides communications in heterogeneous environments. It also provides a routable, enterprise networking protocol and access to the Internet. Its interoperability is its main positive factor.

IPX/SPX

Internet Packet Exchange/Sequenced Packet Exchange is a transport protocol. It is a small and fast protocol on a LAN and used to be the mainstay of Novell NetWare till NetWare 5. Windows NT has
NWLink, which is Microsoft's version of IPX/SPX.

DECnet

DECnet is Digital Equipment Corporation's proprietary protocol. It is the set of hardware and software products that implement the Digital Network Architecture (DNA). It is routable.

AppleTalk

As the name itself indicates, Apple Talk is Apple Computer's proprietary protocol stack. Apple Macintosh computers share files and printers using this protocol in a networked
environment.

NetBIOS

Network Basic Input/Output System is an IBM Session Layer LAN interface. It acts as an application interface to the network.

Originally NetBIOS and NetBEUI were considered one protocol. Later NetBIOS was taken out since it could be used with other routable transport protocols.

NetBEUI

NetBIOS Extended User Interface is a small, fast, and efficient protocol and is supplied with all Microsoft network products. The disadvantage is that it does not support routing.

TCP/IP Basics, the TCP/IP protocol

The TCP/IP protocol is the protocol that holds the Internet together. It is also found in most internal company
networks

How to Install TCP/IP Protocol?

Learn how to install TCP/IP protocol.

What is NetBEUI?

Here you get as clear idea about what is NetBEUI and what are its advantages and disadvantages.

IPX/SPX

Understand more about IPX/SPX here.

Configuring AppleTalk

Learn how to configure AppleTalk.