by Dinesh Thakur Category: Multiple Access

TCP, an acronym for Transmission Control Protocol, corresponds to the fourth layer of OSI reference model. IP corresponds to the third layer of the same model. Each of these protocols has the following features:

TCP-It provides a connection type service. That is, a logical connection must be established prior to communication. Because of this, continuous transmission of large amount of data is possible. It ensures a highly reliable data transmission for upper layers using IP protocol. This is possible because TCP uses positive acknowledgement to confirm the sender about the proper reception of data. The sender keeps on sending data at constant intervals until it receives a positive acknowledgment. 

A negative acknowledgment implies that the failed data segment needs to be retransmitted. 

What happens when a packet is lost on the network and fails to reach its ultimate destination? When host A sends data, it starts a countdown timer. If the timer expires without receiving an acknowledgment, host A assumes that the data segment was lost consequently, host A retransmits a duplicate of the failing segment.

This has also other functions like sequence control, error recovery and control, flow control and identification of port number.

                        TCP Establishes Virtual Circuits

The TCP header includes both source and destination port fields for identifying the applications for which the connection is established. The sequence and acknowledgment Number fields underlie the positive acknowledgment and retransmission technique. Integrity checks are accommodated using the checksum field.

                        Data Segement Format of the TCP Protocol

IP-In contrast to TCP, it is a connection less type service and operates at third layer of OSI reference model. That is, prior to transmission of data, no logical connection is needed. This type of protocol is suitable for the sporadic transmission of data to a number of destinations. This has no functions like sequence control, error recovery and control, flow control but this identifies the connection with port number.

From the above it seems that TCP/IP may be considered as two separate protocols, i.e. TCP and IP. However, TCP actually refers to multiple protocols employed for communications using IP. Therefore, TCP/IP is also referred to as the TCP/IP protocol suit.

                 Correspondance Between TCP-IP model and OSI Model


About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.