Differences between TCP and UDP

In computing, a communication protocol defines the set of rules, syntax, synchronization of communication, and possible error recovery methods. These are the fixed standards that govern the way two devices communicate with each other.

TCP and UDP are the two most widely used internet protocols that we are going to discuss here.

What is TCP

TCP or Transmission Control Protocol is connection-oriented which means a connection between client and server is established before data can be sent. It provides reliable, ordered, error-checked delivery of data. It allows the bidirectional flow of data that means a device communicating over TCP can send and receive data at the same time. TCP is considered one of the most reliable protocols any data loss is automatically detected and corrected by it.

The actual process of establishing a TCP connection takes the following steps –

  • First, a client sends an SYN packet or segment which contains a unique random number to ensure full transmission in the correct order.
  • When this segment is received by the server it agrees to the connection by returning an SYN-ACK packet that includes the client’s sequence number plus 1 and also its own sequence number to the client.
  • Finally, the client acknowledges the receipt of the SYN-ACK packet or segment by sending its own ACK packet that contains the server’s sequence number plus 1.

This whole process of establishing a TCP connection is called the Three-way handshake process. TCP is a perfect protocol for transferring data files, web pages, emails, etc.

What is UDP

UDP or User Datagram Protocol is a simple connectionless internet protocol. The message or data send using UDP are called datagrams. It provides a checksum for data integrity and port numbers for addressing different functions at the source and destination of datagrams. It is an unreliable protocol that doesn’t guarantee delivery, ordering, and duplicate protection of data.

Applications that do not require reliable data stream service can use this protocol instead of using TCP. The UDP is an ideal protocol for real-time communications like broadcast and multicast transmission networks.

TCP vs UDP: The key differences

The following table shows the differences between TCP and UDP –


I hope you understand the basic differences between two mostly used communication protocols i.e. TCP and UDP. Now if you have a query then write us in the comments below.

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