TCP in Networking | TCP Protocol

Transport Layer Protocols-

 

There are mainly two transport layer protocols that are used on the Internet-

 

 

1. Transmission Control Protocol (TCP)
2. User Datagram Protocol (UDP)

 

In this article, we will discuss about Transmission Control Protocol (TCP).

Learn about User Datagram Protocol.

 

Transmission Control Protocol-

 

• TCP is short for Transmission Control Protocol.
• It is a transport layer protocol.
• It has been designed to send data packets over the Internet.
• It establishes a reliable end to end connection before sending any data.

 

Characteristics Of TCP-

 

Point-01:

 

TCP is a reliable protocol.

 

This is because-

• It guarantees the delivery of data packets to its correct destination.
• After receiving the data packet, receiver sends an acknowledgement to the sender.
• It tells the sender whether data packet has reached its destination safely or not.
• TCP employs retransmission to compensate for packet loss.

 

Read More- TCP Retransmission

 

Point-02:

 

TCP is a connection oriented protocol.

 

This is because-

• TCP establishes an end to end connection between the source and destination.
• The connection is established before exchanging the data.
• The connection is maintained until the application programs at each end finishes exchanging the data.

 

Point-03:

 

TCP handles both congestion and flow control.

 

• TCP handles congestion and flow control by controlling the window size.
• TCP reacts to congestion by reducing the sender window size.

 

Read More- TCP Congestion Control

 

Point-04:

 

TCP ensures in-order delivery.

 

• TCP ensures that the data packets get deliver to the destination in the same order they are sent by the sender.
• Sequence Numbers are used to coordinate which data has been transmitted and received.

 

Point-05:

 

TCP connections are full duplex.

 

• TCP connection allows to send data in both the directions at the same time.
• So, TCP connections are Full Duplex.

 

Point-06:

 

TCP works in collaboration with Internet Protocol.

 

• A TCP connection is uniquely identified by using-

Combination of port numbers and IP Addresses of sender and receiver.

• IP Addresses indicate which systems are communicating.
• Port numbers indicate which end to end sockets are communicating.
• Port numbers are contained in the TCP header and IP Addresses are contained in the IP header.
• TCP segments are encapsulated into an IP datagram.
• So, TCP header immediately follows the IP header during transmission.

 

Point-07:

 

TCP can use both selective & cumulative acknowledgements.

 

• TCP uses a combination of Selective Repeat and Go back N protocols.
• In TCP, sender window size = receiver window size.
• In TCP, out of order packets are accepted by the receiver.
• When receiver receives an out of order packet, it accepts that packet but sends an acknowledgement for the expected packet.
• Receiver may choose to send independent acknowledgements or cumulative acknowledgement.
• To sum up, TCP is a combination of 75% SR protocol and 25% Go back N protocol.

 

Point-08:

 

TCP is a byte stream protocol.

 

• Application layer sends data to the transport layer without any limitation.
• TCP divides the data into chunks where each chunk is a collection of bytes.
• Then, it creates a TCP segment by adding IP header to the data chunk.
• TCP segment = TCP header + Data chunk.

 

Point-09:

 

TCP provides error checking & recovery mechanism.

 

TCP provides error checking and recovery using three simple techniques-

1. Checksum
2. Acknowledgement
3. Retransmission

 

Also Read- Checksum

 

To gain better understanding about Transmission Control Protocol,

Watch this Video Lecture

 

Next Article- TCP Header

 

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