Internet network-level protocols

The Internet network-level protocols handle machine-to-machine communication.

In other words, this layer implements TCP/IP routing. These protocols accept requests to send packets (along with the network address of the destination machine) from the Transport layer, convert the packets to datagram format, and send them down to the Network Interface layer for further processing.

Figure 1. Network layer of the TCP/IP Suite of Protocols
Network layer of the TCP/IP Suite of Protocols
This illustration shows the various layers of the TCP/IP Suite of Protocols. From the top, the application layer consists of the application. The transport layer contains UDP and TCP. The network layer contains the network (hardware) interface. And finally, the hardware layer contains the physical network.

TCP/IP provides the protocols that are required to comply with RFC 1100, Official Internet Protocols, as well as other protocols commonly used by hosts in the Internet community.

Note: The use of Internet network, version, socket, service, and protocol numbers in TCP/IP also complies with RFC 1010, Assigned Numbers.