Differences between TCP and UDP

	TCP	UDP
Full Form	Transmission Control Protocol	User Datagram Protocol
Function	Connection based protocol which is used to transport message across the internet from one computer to another	Non-Connection based protocol used in message transport or transfer
Working	TCP connection is established via a three way handshake, which is a process of initiating and acknowledging a connection.	UDP uses a simple transmission model without implicit handshaking dialogues for guaranteeing reliability, ordering, or data integrity
Example	HTTP, HTTPS, FTP, SMTP, Telnet, etc.	DNS, DHCP, FTP, SNMP, RIP, VOIP, etc.
Usage	TCP is used in case of non-time critical applications	UDP is used for games or applications that require fast transmission of data
Ordering	TCP rearranges data packets in the order specified	UDP has inherent order as all packets are independent of each other. If ordering is required, it has to be managed by the application layer
Transfer Speed (mbps)	Slower than the speed of UDP	It is faster than TCP because there is no error-checking for packets
Error Checking	TCP does error checking	UDP does error checking, but no recovery options
Reliability	Guarantees that the data transferred remains intact and arrives in the same order in which it was sent	There is no guarantee that the messages or packets sent would reach at all
Connection Reliability	Two way connection reliable	One way Connection Reliable
Weight	TCP requires three packets to set up a socket connection, before any user data can be sent. TCP handles reliability and congestion control	UDP is lightweight. There is no ordering of messages, no tracking connection, etc. It is a small transport layer designed on top of IP
Data Flow Control	TCP does Flow Control	No flow control
Header Size	20 bytes	8 bytes
Streaming of Data	Data is read as a byte stream. No distinguishing indications are transmitted to signal message (segment) boundaries	Packets are sent individually and are checked for integrity only if they arrive. Packets have definite boundaries
Application	Web browsing, email and file transfer are common application that make use of TCP. TCP is used to control segment size, rate of data exchange, flow control and network congestion. TCP is preferred where error connection facilities are required at network interface level	UDP is commonly used in Domain Name System, Voice over IP, Trivial File Transfer Protocol and Online Games. UDP is largely used by time sensitive applications as well as by servers that answer small queries from huge number of clients. UDP is compatible with packet broadcast - Sending to all on a network and multicasting – sending to all subscribers.