Skip to main content

What is OSI(Open System Interconnection) Model

OSI (Open System Interconnection)

 

OSI Model - upper and lower layers -

Layers of the OSI Model

Definition: The OSI model defines internetworking in terms of a vertical stack of seven layers. Upper layers of the OSI model represent software that implements network services like encryption and connection management. Lower layers of the OSI model implement more primitive, hardware-oriented functions like routing, addressing, and flow control. 


Data communication in the OSI model starts with the top layer of the stack at the sending side, travels down the stack to the sender's lowest (bottom) layer, then traverses the physical network connection to the bottom layer on the receiving side, and up its OSI model stack.

 

The OSI model was introduced in 1984. Designed to be an abstract model and teaching tool, the OSI model remains a useful for learning about today's popular network technologies like Ethernet and protocols like IP.



Examples: Internet Protocol (IP) corresponds to the Network layer of the OSI model, layer three. TCP and UDP correspond to OSI model layer four, the Transport layer. Lower layers of the OSI model are represented by technologies like Ethernet. Higher layers of the OSI model are represented by application protocols like TCP and UDP.

 

1. Short for Open System Interconnection, OSI is a network model developed by ISO in 1978 where peer-to-peer communications are divided into seven layers. Each layer performs a specific task or tasks, and builds upon the preceding layer until the communications are complete. Below are the purposes of each of the seven layers.

 

1 - Physical layer - responsible for the electrical, mechanical, and timing across the link.
2 - Data link layer (also known as the link layer) - responsible for transmitting data across a link.
3 - Network layer - responsible for routing information through the network and allowing systems to communicate.
4 - Transport layer - responsible for transferring information between endpoints on the network and deals with errors such as lost or duplicate packets.
5 - Session layer - responsible for managing a session between two applications.
6 - Presentation layer - responsible for the data formatting and display, allowing for compatibility.
7 - Application layer - responsible for user interaction. An example of an OSI application is the FTAM.

2. Short for Open-Source Initiative, OSI is a non-profit corporation dedicated to managing and promoting Open Source.

Popular posts from this blog

IT EMPLOYEE HEALTH ISSUES

An increasing number of IT professionals have been finding it difficult to handle emotional stress, according to experts. An ‘occupational hazard,' the stress related to work needs to be addressed without delay, they emphasise.

“Coping with stress and striving for mental health welfare should be a matter of concern for all and not treated simply as a lifestyle problem of the ‘IT phenomenon',” says Nithya Chandrasekaran, a consultant physician for many IT companies in the city. Post-recession, employees feel pressured to perform well.

Regular occupational problems such as wrist problems due to constant handling of the mouse, slip disc and eye fatigue are common now, but handling stress that arises owing to fear of losing job or to cope with the increasing competition, affects the employee's performance, eventually, taking a major toll on his health, doctors explain.

The project that K. Balajee (29) was handling was pulled off after six months of its inception. Currently ma…

Internet Safety Tips and Rules

Why is it important to stay safe online?

Most of us are ‘connected’ via our laptops, mobile phones, tablets or personal computer. The potential for the internet to be a valuable and a fun resource for entertainment, making friends, keeping in touch and learning is huge. But if you use the internet, you could be at risk of illegal activity or abuse - be it bullying, fraud or something more serious. Unlike seeing someone face to face, on the net, people aren't always what they first seem.

In the same way you learn about safety when you leave the house, it is important to learn how to stay safe online. These are skills that will stay with you for life.



Internet Safety Tips for Kids and Teens
1. Spend time having fun with your parents online and helping them understand technology!
2. Never post your personal information, such as a cell phone number, home number, home address, or your location on any social networking site or through mobile apps like Snapchat or Instagram.
3. Never me…

Cyber Crime

Cyber Crime is a fast-growing area of crime.More and more criminals are exploiting the speed, convenience and anonymity of the Internet to commit a diverse range of criminal activities that know no borders, either physical or virtual, cause serious harm and pose very real threats to victims worldwide.

What is the Cyber Crime? Cyber crime encompasses any criminal act dealing with computers and networks (called hacking).  Additionally, cyber crime also includes traditional crimes conducted through the Internet.  For example; hate crimes, telemarketing and Internet fraud, identity theft, and credit card account thefts are considered to be cyber crimes when the illegal activities are committed through the use of a computer and the Internet.

Identity theft
Identity theft and fraud is one of the most common types of cyber crime. The term Identity Theft is used, when a person purports to be some other person, with a view to creating a fraud for financial gains. When this is done online on the…