TCP/IP actually divides the message up into smaller parts or packets and puts an address on each packet. The router sends each packet to the destination computer, but each packet may not take the same path to get to the destination computer. This method allows the entire message to be delivered much more quickly to the destination computer.

Splitting up the message into packets is called packet switching. The destination computer reassembles the packets into the complete message. If it finds an error in the message, it can ask the sending computer to resend the bad packet.