How is TCP protocol a reliable protocol ?

[Udyami]

I am a BE student and till now I am learning programming language. But in further second semesters I will have computer networks. I have heard that my college teachers does not teach well. So I want to know a bit about the networks, so I will start with the TCP/ IP first. I know a bit about it. It is a upper level protocol and is a bit safe than IP protocol can any one explain in brief something about these protocols.Waiting for your replies.

[Milton.J]

TCP protocol is a connection oriented , upper level and reliable protocol. TCP stands for transfer control . It is an higher level protocol and is used with lower level protocol such as IP and both are combined to form a TCP/IP protocol. TCP/IP protocol sends the data in form of packets. This packets are of definite size and contain the actual data and the TCP/ IP header with an option. The size of the header will be of 20 bytes without the optional part. If it contains the options, the size of the header will be of 60 bytes. If you want to calculate the size of the actual data the you can deduct the size of the header file from the total size of the packet

[Spyrus]

Let me correct you the packets in the TCPIP protocol are called as segments The TCP/IP protocols indeed a reliable protocol , because it acknowledged all the packets you send to the receiver. Before you understand it let me explain you some basic things with an example. Suppose you wish to send 4000bytes of data and you are asked to send 2000 bytes in the first segments and then 1000bytes and another 1000 bytes in the last then you can number the segment , a byte number can be randomly put. A segment it is recognized by a sequence number of each segment , which is the first byte number of each segment , here in this case you can put 2001, if you begin a byte number with 2001. And there is one more number called as Acknowledgment number. If you send the data across a network whether it reaches the original recipient or not is determined by the Acknowledgment number . The Acknowledgment number is always cumulative increment to the sequence number of the segment.

[Pabloa]

Why do not you explain in simpler terms , you have included all the technical terms and jargon. The Acknowledgment number is always one number greater than the sequence number . Consider the above given example , if you have sent a segment with a sequence number as 2001 to 2100 over the network. Once it reaches the recipient , the receiver will check it and will send a response to the sender as ACK 2101, which states that the segment up to 2100 have reached safe and sound , now it expects 2101 segment to be send over the network. Thus it is a reliable protocol and ensures the security of the packets..

[Zachary]

Hello friends. you have indeed mentioned all the basic features of TCP/IP protocol but not actually mentioned how is much more reliable to use over a network to transform the packets. It provides error control , flow control and fragmentation of packets. It provides flow control at the time of sending and receiving of packets in case of corrupted packet, or lost packet or lost acknowledgment. The error control is done with the help of a process called check sum , the binary value produces after adding the check sum value must be equivalent to zero or else the packet is discarded. The fragmentation is done in which the segments are divided into small packets and then sent over the network in case if any protocol does not accept in large volume. The fragmentation of packet is done on the basis of maximum transfer unit or MTU.