The History Of Osi Reference Model

Published Date: 02 Nov 2017

Due to recent advancements in wireless communication have enabled development of low power, low cost and various sensor nodes which are in small size and communicate into a shorter distances. Wireless sensor network is a combination of different nodes which are collaborate into a network. Each node is composed of various types of memories such as flash, data and program memories. It also consists of different types of sensors, actutators and a power source. Architecture of wireless sensor network communication:

In the sensor field all the sensor nodes are scattered. The sensor nodes which are scattered collects the data and sends data back into end user. Multihop infrastructureless architecture is used to send data back into end user. The sink communicates with task manager node through satellite or internet.

Sensor nodes scattered in sensor field

Protocol stack unites routing awareness, power and accomidates data with network protocols. It also communicates power effectively in the wireless medium. Protocol stack subsists of transport layer, application layer, data link layer, network layer, physical layer, mobility management plane, power management plane and task management plane.

Sensor network protocol stack

Application Layer:

Application layer use most common network programs which communicates with other programs with in the network. In the application layer data passes in the format which generally used by application and encodes into standard protocol. In this layer only particular programs are considered to run. These protocols included are FTP (File transport ), HTTP (World wide web), SMTP (Email), DNS (IP address), SSH (Secure remote login). Once data is encoded into application layer protocol it passes to next layer of internet protocol stack.

Transport layer:

In the transport layer protocols solves various problems such as accuracy, fidelity, security and confirms data arrives in correct format. TCP is connection oriented, reliable and ensures data arrives in order, undamaged and complete. TCP continuously measures load of the network to avoid overloading of the network. TCP delivers complete data in the particular sequence. UDP is connection less protocol. It is unreliable and do not verify packets reached the destination and there is no gurantee that the packet reaches destination in order. UDP is used in applications such as video and audio.

Network layer:

Network layer solves problem of getting data over a single network. In the network layer another functionality was joined such as data transfered from source network reaches destination network safely. In the TCP/IP protocol suite internet protocol implements task of getting data from source network to destination network.

Data link layer:

The data link layer determines how data is transferred over physical layer which includes framing i.e specific pattern are marked at end and the start of the packets. For example in the Ethernet packet header includes fields which specifies which machine in the network destined for a packet.

Physical layer:

Physical layer illuminates all the physical charecteristics of conventions such as fibers, wires, optical links etc and other details such as channel codes, connectors and modulation. Ip protocol suite does not include physical layer.

OSI Reference model:

In 1984 International organization for Standardization (ISO) introduced the OSI reference model describes how data is passed from one networking component to other networking component. When the user enters data and converted into light or electrical signals. OSI reference model is commonly used in troubleshooting tool. International organization for standardization (ISO) developed seven layer model to undestand how data is transferred between the networking devices.

OSI Reference model

Application layer:

The seventh layer of OSI refernce model is application layer. It accomidates interface that person use to collobarate with application. This interface may be graphics based or command line based. Web browsers use graphics based interface where as Cisco IOS switches and routers uses command line based interface. Examples of application layer include File transfer protocol (FTP), Secure Shell (SSH) and telenet.

Presentation layer:

The sixth layer of OSI reference model is presentation layer. Presentation layer defines how information is passed and given to the user interface that she or he is using. This layer illustrates how different forms of graphics, texts, audio and video information is passed and used exactly by application layer. The examples of presentation layer protocol includes BMP, ASCII, JPEG, MPEG.

Session layer:

Session layer is the fifth layer in the OSI reference model. The session layer initiates the setup and disassembly the connections. In order to perform the functions session layer illustrates whether data is local to computer or must be retrieved or pass to remote networking component. Afterwards session layer is responsible for initiating the connections. It is also responsible to differentiate various network connections and ensures data is passed to exact connection and to obtain data from connection and passing it to exact local application. In order to didassembly connections or to set up connections session layer communicates with transport layer. Examples of session layer includes NFS and RPCs.

Back ground research:

Main problems involved in car parking: