What are examples of TCP and UDP in real life?

TCP:

• World Wide Web(HTTP)
• E-mail (SMTP TCP)
• File Transfer Protocol (FTP)
• Secure Shell (SSH)

UDP:

• Domain Name System (DNS)
• Streaming media applications such as movies
• Online multiplayer games
• Voice over IP (VoIP)
• Trivial File Transfer Protocol (TFTP)

UDP is mailing a letter at the post office.

TCP is mailing a letter with a return receipt at the post office, except that the post master will organize the letters in-order-of mailing and only deliver them in-order.

Well, it was an attempt anyway.

UDP: Anything where you don't care too much if you get all data always

• Tunneling/VPN (lost packets are ok - the tunneled protocol takes care of it)
• Media streaming (lost frames are ok)
• Games that don't care if you get every update
• Local broadcast mechanisms (same application running on different machines "discovering" each other)

TCP: Almost anything where you have to get all transmitted data

• Web
• SSH, FTP, telnet
• SMTP, sending mail
• IMAP/POP, receiving mail

EDIT: I'm not going to bother explaining the differences, since you state that you already know and every other answer explains it anyway :)

REAL TIME APPLICATION FOR TCP:

Email:

Reason: suppose if some packet(words/statement) is missing we cannot understand the content.It should be reliable.

REAL TIME APPLICATION FOR UDP:

video streaming:

* **Reason: ***suppose if some packet(frame/sequence) is missing we can understand the content.Because video is collection of frames.For 1 second video there should be 25 frames(image).Even though we can understand some frames are missing due to our imagination skills. Thats why UDP is used for video streaming.