Network Layer

The layer corresponding to the OSI network layer is the TCP/IP protocol is sometimes called the network layer, sometimes the internetwork layer, and sometimes the internet layer. Whatever it is called, it contains just a few protocols; the main protocol is called internetwork protocol (IP). The protocol is responsible for the creating network-layer packets called IP datagrams and sending them to the destination. The datagrams travel from network to network (LAN to LAN) and may reach the destination in or out of order. The upper layers are responsible for ordering the receiver packets. The intermediate nodes are responsible for routing the datagram through the most appropriate routes without changing the data portion of the datagram.