Tale of nets - 03 ( TCP )

Now, because we know what is called as a protocol. Let’s see some of the protocols that are being used in the networking. Sometimes these may sound more technical but bear with it coz sometime you have to make the dots hoping that someday they will be connected just like Steve Jobs said.

            Before going to that we have make some new terms. They are client and the server. It’s also not that hard concept to understand. Imagine you have a great pizza place near your house and you want to orders or request some pizzas to watch the game. What you do is you call the pizza place tell them what you want. If you are lucky and they haven’t ran out of pizzas you will get or receive your pizzas through a delivery guy. If they haven’t the particular pizza that you ordered you will get a no for an answer and that is something page requested not found error in the web. Obviously what you ordered is not there. So here you are the client and pizza place is the server. What client does is request something and what server does is replying for that requests and if the requested thing are there just send them and if not send an error message.

TCP (Transmission Control Protocol)

      
        This is a connection oriented protocol. That means whenever the client want to talk with the server it has to make a connection with the server. Say client is asking 3 web pages from the web server, it has to make 3 connections to do that.

This uses something called 3way handshaking. It’s simply like this.

• First the client asks for a connection request from the server. It’s like asking server “Hey there sever, can we talk for a while?” and server receives the message. (Client sends Synchronized packet to server and server receives it) SYN

• If the server is in a mood to connect with other clients he will send a message to the requested client.(Server sends Synchronized – Acknowledgement to the client and he gets the message) SYN-ACK

• Client sends Acknowledgement and server receives the Acknowledgement. ACK

And voila. :D

A TCP connection is established between client and server.

           Normally when data or connection request or connection reply or whatever that is transmitted between clients and servers they are being sent as packets. When a TCP protocol is used what it uses is TCP packets. In a TCP packet lots of details are there like address numbers of the  source ports, destination ports, sequence numbers of the packets and so much details.

We don’t always use TCP protocol for everything. Generally its good for sending sequenced messages or packets, to send the data with delivery guarantee (because acknowledgement is there) ant to filter traffic.


Time gets into serious things now :) ......