Protocols

Protocols are set of rules and procedures for communicating. There are many protocols are used but some are commonly used protocols. They are:
TCP/IP
NetBEUI
DECnet
X.25
IPX/SPX and
AppleTalk
But the most important protocol is TCP/IP. In this protocol data transmission is managed by dividing the data into different pieces called packets. Each packet of data contains a part of actual data, source computer address, destination address, and information for reassembling data at destination computer. These packets of data travel along the fastest available path in the network. This type of data transmission is called packet switching and is used in internet communication. This is the reason that the protocol is also called Internet Protocol.
TCP/IP is divided into 3 usable classes and 2 experimental classes. Class A, B, C are usable classes and D, E are experimental classes. We can not use experimental classes in network.
Classes Range
A 1.X.X.X 126.X.X.X
B 128.X.X.X 191.X.X.X
C 192.X.X.X 223.X.X.X
D 224.X.X.X 239.X.X.X
E 240.X.X.X 254.X.X.X
127.X.X.X is used for troubleshootin