The internet layer derives its name from its function facilitating internetworking, which is the concept of connecting multiple networks with each other through gateways.
The internet layer does not include the protocols that fulfill the purpose of maintaining link states between the local nodes and that usually use protocols that are based on the framing of packets specific to the link types. Such protocols belong to the link layer. Internet-layer protocols use IP-based packets.
Example of usage – “In Version 4 of the Internet Protocol (IPv4), during both transmit and receive operations, IP is capable of automatic or intentional fragmentation or defragmentation of packets, based, for example, on the maximum transmission unit (MTU) of link elements. However, this feature has been dropped in IPv6, as the endpoints of the communication, the hosts, now have to perform path MTU discovery and assure that end-to-end transmissions don’t exceed the maximum discovered.”