Hi! I will try to explain the basics of both of these protocols, without going too much deep, but a bit. TCP and UDP are all running on IP. Let's say for now that IP is the Internet Protocol and it is in charge of the delivery of all Internet packets on the Internet, between any Internet connected computer. UDP UDP is in charge of the basic delivery, really, really the basic delivery. It creates one concept to allow multiple applications on one computer to communicate without being interfered by each other using ports. Basically, it's just little boxes waiting next to each app. Otherwise, UDP isn't doing so good: any packet can be lost - it means that it will never reach the recipient... - or the same packet can be sent twice to the recipient while you only sent once, and it also send packets out of order. But it is still nice because you have lot of control about the delivery etc. TCP TCP is more structured. It borrows the UDP concept of ports, but it does only connections. Basically, TCP ensures that data you send on one connection, in two ways, is safe. It reorder packets, if packets are lost, they get resent, and duplications are removed. However, the big problem is that it isn't flexible. If you want to avoid packets to get resent because your information - like voice in a voice call - is valid only few milliseconds, you can't use TCP at all.