The third layer of the seven layers of Open Systems Interconnection (OSI) network model is the Network layer. The Network layer of the OSI model is responsible for managing logical addressing information in the packets and the delivery of those packets to the correct destination. Routers, which are special computers used to build the network, direct the data packet generated by Network Layer using information stored in a table known as routing table. The routing table is a list of available destinations that are stored in memory on the routers. The network layer is responsible for working with logical addresses. The logical addresses are used to uniquely identify a computer on the network, but at the same time identify the network that system resides on. The logical address is used by network layer protocols to deliver the packets to the correct network. The Logical addressing system used in Network Layer is known as IP address.

IP addresses are also known as Logical addresses or Layer 3 addresses.

Layer 4. Transport Layer