Protocols are the rules and procedures for communicating. For two computers to communicate, they must speak the same language and agree on the rules of communication. Each protocol has a different purpose and function. When a set of protocols work together cooperatively, it is called a protocol suite or protocol stack. Two of the most common protocol suites are
(1) TCP / IP, the internet protocol suite
(2) IPX / SPX, the Novell Netware and Intranetware protocol suite.
Protocols that use connectionless delivery place the data on the network and assume it will get through. Data is sent in packets. Here packets are called datagrams. This method is fast but not reliable Connection-oriented protocols are slower but more reliable. A connection is established between the two computers before communication begins. then data is sent. As each packet reaches the destination, it's receipt is acknowledge.