Tcp Tutorial-6

packet is a physical object or thing which moves on a physical medium like a wire. There is a remarkable

difference between a Packet and a Datagram, but it is beyond the scope of this book. To make things easier I will use only the term datagram (Actually this is the official term.)while discussing various protocols.

Two different main protocols are involved in transporting packets from source to destination.

1.) The Transmission Control Protocol or the TCP Protocol 2.) The Internet Protocol or the IP protocol.

Besides these two main protocols, the Physical Layer and the Ethernet Layer are also indispensable to data transfer.

THE TRANSPORT LAYER

The TCP protocol

The Transmission Control Protocol is responsible for breaking up the data into smaller datagrams and putting the datagrams back to form usable data at the destination. It also resends the lost datagrams to destination where the received datagrams are reassembled in the right order. The TCP protocol does the bulk of work but without the IP protocol, it cannot transfer data.

Let's take an example to make things more clearer. Let's say your Internet Protocol Address or IP address is xxx.xxx.xxx.xxx or simply x and the destination's IP is yyy.yyy.yyy.yyy or simply y. Now As soon as the three-way connection is established between x and y, x knows the destination IP address and also the Port to which it is connected to. Both x and y are in different networks which can handle different sized packets.