Transmission Control Protocol (TCP) defines a certain way for messages to be handled on the
internet as part of the
TCP-IP protocol stack. As opposed to
UDP, TCP assures receipt of messages by sending additional messages when packet
?s are sent and recieved so each packet is verified. This takes a certain amount of extra processing power and
bandwidth, but assures delivery, somewhat like registered mail at the post office.
Further reading: [RFC793]