Mar 11
25
To reduce the networking and it’s design complexity most of the networks are organized into series of layered structure. At each important stage of transferring data from one machine to another machine in computer networking there is a layered concept. This layered structure is just to fulfill the successful completion of the sending and receiving data packets from one machine to another machine.
I was confused about these layered concept of networking at the time of my studies. I was thinking that there will be many layers of physical machines to complete the process of computer networking. Actually there are no physical layers. We have called each stage of processing in computer networking is called one layer. After completion of all the stages of processing for a packet, then about to send the physical lines are required to send the packet to another machine. This stage is called physical layer.
There are 7 layered concept existing in actual computer networking. Each of these layers built upon the another layer. The number of the layers and the name of the each layer and the content of each layer and the function of each layer different from one network to another network. But in all networks the purpose of the each layer is to provide certain services to the higher layers. Layer x on one machine will carries a conversation with layer x on another machine. The rules & conventions used in this conversation are known as the layer x protocol.
Generally , a protocol is an agreement between the communicating parties on how communication is to be proceeded. As analogy, when a girl is introduced to a boy, she may choose to stick out her hand. He, in turn, may decide either to catch it up to help her or to kiss it. This depends upon the situation and relation between them. She may offered her hand by expecting a kiss from his boy friend or asking her colleague to help her to come up from a lower step. Violating the protocol will make communication more difficult and may become communication is impossible. So the protocol is very important either in our life or in computer networking.
No data is directly transferred from one layer on machine to same layer on another machine. Each layer passes data and control information to the layer immediately below it, until the lowest layer is reached. Last layer is called physical layer through which actual communication occurs.
There is an interface exists between each pair of adjacent layers. This interface defines which are all the primitive services and operations the lower layer provides to the upper layer. One of the most important consideration while implementing network architecture is defining clean interfaces between the each pair of layers. Network designers decided no. of layers included in network and what each layer should do at the time of implementing network infrastructure. So each layer should perform specific collection of well understood functions. A set of layers and protocols is called a network infrastructure. This specification of an architecture is helping the programmers to write a program or build the hardware for each layer and so that it will correctly obey the appropriate protocol.
