Internet Protocol

Unlike TCP, IP is an unreliable, connectionless protocol.

IP's job is too send and route packets to other computers.

IP packets are independent entities and may arrive out of order or not at all. It is TCP's job to make sure packets arrive and are in the correct order.

The application layer data is segmented in the TCP layer, the TCP header is added, the packet continues to the IP layer, the IP header is added, and then the packet is transmitted across the Internet.