Host to Network Layer

Network layer

In computer networking, Network layer is the layer 3 of the seven layer OSI model. For routing packets delivery including routing through intermediate routers, the networking layer is responsible, whereas the data link layer is responsible for media Access control, flow control and error checking.  While maintaining the quality of service functions, the network layer provides the functional and procedural means of transferring variable length data sequences from a source to destination host through one or more networks. We will discuss about Host of Network layer in coming Para.

Host to Network Layer

The host to network layer is the bottom layer of the TCP/IP protocol stack to the physical network and lies below the internet layer. As it is not officially defined, it varies from implementation to implementation, with vendors supplying their own version. It is also known as network interface layer. A function of this layer is to connect the host to the network and inform the upper layers so that they could start sending the data packets. And this layer varies from network to network.

Functions of Network Layer

Network layer is provides internet working. Network layer adds logical address of the sender and receiver to each packet, when packet is sent outside the network. Network addresses are assigned to local devices by network administrator and assigned dynamically by special server called DHCP (Dynamic Host configuration protocol).  The host of the network layer needs to have the unique address which uses to determine, where it is. From the hierarchical system, this address will normally be assigned. On the internet addresses are known as Internet protocols.

TCP/IP Model

The current internet is based on a TCP/IP reference model. The two protocols of this model are TCP and IP. TCS stands for Transmission control protocol and IP stands for Internet protocol. The architecture or model was defined by the US department of defense and is used by ARPANET (Advanced research project agency network). The network should connect multiple networks together and the connection should withstand till the source and destination machines are functioning. The architecture should be so flexible, that it should be able to transfer data among different hardware or software platforms.

Internet Layer

It is similar to network layer of OSI model in functionality. It allows the hosts to submit the packets to the network and using any possible route the packets should travel independently. It is responsibility of higher layer to arrange these packets in proper order.  The order in which the packets arrive at destination can be different from the order in which they were sent.

Questions:

• What is network layer?
• What are the functions of network layer?