Difference Between TCP and UDP

What is TCP?

TCP is known as the transmission protocol. It is a transport protocol on the top of the IP which helps in the reliable transmission of data or packets.

The mechanism of TCP is to solve many problems arising from packet-based messaging like out-of-order, duplicate, corrupted, or lost packets, etc. TCP helps in organizing data and ensures secure transmission between client and server.

The integrity of data sent over is guaranteed by TCP, regardless of its amount. Due to this, it is useful in transmitting data from other higher-level protocols which need the arrival of all transmitted data.

TCP is necessary for all computer applications because it helps in data transmission. All major internet-dependent applications like the world wide web, email, file transfer, and remote administration rely on TCP. It is connection-oriented.

However, there are a few areas for improvement in TCP,  like the refusal of services by TCP. TCP is vulnerable to getting hijacked. TCP help to prevent network overcrowding.

What is UDP?

UDP is a communication protocol called a user datagram protocol and helps establish low latency and tolerate data loss connection between applications on the internet.

Data packets are transmitted over a network using this connectionless internet protocol. A trustworthy user datagram protocol is connectionless and doesn’t demand a session before data transmission.

Additionally, UDP does not include any error-checking mechanisms and neither guarantees nor orders the delivery of packets. UDP fastens transmissions by permitting the data transfer before the receiving party agrees.

However, UDP is suitable for uses where error checking and corrections are either unnecessary or done by the application.

Additionally, UDP is necessary for time-sensitive applications because delayed or retransmission of packets is preferable to dropping packets which is not a good option in a real-time system.

Difference Between TCP and UDP

TCP and UDP are transmission protocols that help transmit data between server and application. However, there is a difference between their working ability and mode.

TCP is a slower protocol in data transmission speed, while UDP is much faster and more efficient than TCP. 

TCP is not helpful in broadcasting, while UDP offers to broadcast.

Since TCP manages message recognition and retransmission in the event of lost elements, it is more reliable. Thus, there is no data at all.

At the same time, UDP lacks the concepts of acknowledgment, time out, and replay. So, it cannot ensure that information has reached the intended destination.

TCP ensures the retransmission of lost data, while UDP cannot retransmit lost DATA.

Comparison Between TCP and UDP

Parameter of ComparisonTCPUDP
NameTCP Transmission Control Protocol.UDP User Datagram Protocol
DefinitionIt is a transport protocol at the top of the IP which helps in the reliable transmission of data or packets.It helps to establish low latency and tolerate data loss connection between applications on the internet.
FunctionTCP is a message that makes its way from one computer to another through an internet connection. It is internet dependent.At the same time, UDP is a transport protocol used in message transfer or transport. It is not connection-dependent.
UsageMost applications require high reliability and relatively less critical transmission time and are well suited for TCP.Like games, applications that need a fast and efficient transmission are suitable for UDP.    
Protocols usedHTTP, HTTPS, FTP, SMTP, TelnetDNS, DHCP, TFTP, SNMP, RIP, and VOIP.
Header SizeThe header size of TCP is 20 bytes.  The header size of UDP is 8 bytes.  
Error CheckingTCP makes error checking. recovery.    Error checking is done by UDP, which simply discards erroneous packets that do not recover them.  
ReliabilityIt is reliable.It needs to be more reliable.


  1.  Vinton G. Cerf; Robert E. Kahn (May 1974). A Protocol for Packet Network Intercommunication (PDF). IEEE Transactions on Communications. 22 (5): 637–648. doi:10.1109/tcom.1974.1092259. Archived from the original (PDF) on March 4, 2016.
  2. ^ Bennett, Richard (September 2009). “Designed for Change: End-to-End Arguments, Internet Innovation, and the Net Neutrality Debate” (PDF). Information Technology and Innovation Foundation. p. 11. Retrieved 11 September 2017.