As computing technology evolved and the concept of linking multiple computers together into a “network” that could share data came into being, it was clear that a model was needed to define and enable those connections. Enter the OSI model in computer network idea.
This model allows various devices and software to “communicate” with one another by creating a set of universal rules and functions. Let’s dig into what the model entails.
History of the OSI Model
In the late 1970s, the continued development of computerized technology saw many companies start to introduce their own systems. These systems stood alone from others. For example, a computer at Retailer A has no way to communicate with a computer at Retailer B, with neither computer being able to communicate with the various vendors and other organizations within the retail supply chain.
Clearly, some way of connecting these standalone systems was needed, leading to researchers from France, the U.S., and the U.K. splitting into two groups – The International Organization for Standardization and the International Telegraph and Telephone Consultive Committee.
In 1983, these two groups merged their work to create “The Basic Reference Model for Open Systems Interconnection (OSI).” This model established industry standards for communication between networked devices, though the path to OSI’s implementation wasn’t as clear as it could have been. The 1980s and 1990s saw the introduction of another model – The TCP IP model – which competed against the OSI model for supremacy. TCP/IP gained so much traction that it became the cornerstone model for the then-budding internet, leading to the OSI model in computer network applications falling out of favor in many sectors. Despite this, the OSI model is still a valuable reference point for students who want to learn more about networking and still have some practical uses in industry.
The OSI Reference Model
The OSI model works by splitting the concept of computers communicating with one another into seven computer network layers (defined below), each offering standardized rules for its specific function. During the rise of the OSI model, these layers worked in concert, allowing systems to communicate as long as they followed the rules.
Though the OSI model in computer network applications has fallen out of favor on a practical level, it still offers several benefits:
- The OSI model is perfect for teaching network architecture because it defines how computers communicate.
- OSI is a layered model, with separation between each layer, so one layer doesn’t affect the operation of any other.
- The OSI model offers flexibility because of the distinctions it makes between layers, with users being able to replace protocols in any layer without worrying about how they’ll impact the other layers.
The 7 Layers of the OSI Model
The OSI reference model in computer network teaching is a lot like an onion. It has several layers, each standing alone but each needing to be peeled back to get a result. But where peeling back the layers of an onion gets you a tasty ingredient or treat, peeling them back in the OSI model delivers a better understanding of networking and the protocols that lie behind it.
Each of these seven layers serves a different function.
Layer 1: Physical Layer
Sitting at the lowest level of the OSI model, the physical layer is all about the hows and wherefores of transmitting electrical signals from one device to another. Think of it as the protocols needed for the pins, cables, voltages, and every other component of a physical device if said device wants to communicate with another that uses the OSI model.
Layer 2: Data Link Layer
With the physical layer in place, the challenge shifts to transmitting data between devices. The data layer defines how node-to-node transfer occurs, allowing for the packaging of data into “frames” and the correction of errors that may happen in the physical layer.
The data layer has two “sub-layers” of its own:
- MAC – Media Access Controls that offer multiplexing and flow control to govern a device’s transmissions over an OSI network.
- LLC – Logical Link Controls that offer error control over the physical media (i.e., the devices) used to transmit data across a connection.
Layer 3: Network Layer
The network layer is like an intermediary between devices, as it accepts “frames” from the data layer and sends them on their way to their intended destination. Think of this layer as the postal service of the OSI model in computer network applications.
Layer 4: Transport Layer
If the network layer is a delivery person, the transport layer is the van that the delivery person uses to carry their parcels (i.e., data packets) between addresses. This layer regulates the sequencing, sizing, and transferring of data between hosts and systems. TCP (Transmission Control Protocol) is a good example of a transport layer in practical applications.
Layer 5: Session Layer
When one device wants to communicate with another, it sets up a “session” in which the communication takes place, similar to how your boss may schedule a meeting with you when they want to talk. The session layer regulates how the connections between machines are set up and managed, in addition to providing authorization controls to ensure no unwanted devices can interrupt or “listen in” on the session.
Layer 6: Presentation Layer
Presentation matters when sending data from one system to another. The presentation layer “pretties up” data by formatting and translating it into a syntax that the recipient’s application accepts. Encryption and decryption is a perfect example, as a data packet can be encrypted to be unreadable to anybody who intercepts it, only to be decrypted via the presentation layer so the intended recipient can see what the data packet contains.
Layer 7: Application Layer
The application layer is a front end through which the end user can interact with everything that’s going on behind the scenes in the network. It’s usually a piece of software that puts a user-friendly face on a network. For instance, the Google Chrome web browser is an application layer for the entire network of connections that make up the internet.
Interactions Between OSI Layers
Though each of the OSI layers in computer networks is independent (lending to the flexibility mentioned earlier), they must also interact with one another to make the network functional.
We see this most obviously in the data encapsulation and de-encapsulation that occurs in the model. Encapsulation is the process of adding information to a data packet as it travels, with de-encapsulation being the method used to remove that data added data so the end user can read what was originally sent. The previously mentioned encryption and decryption of data is a good example.
That process of encapsulation and de-encapsulation defines how the OSI model works. Each layer adds its own little “flavor” to the transmitted data packet, with each subsequent layer either adding something new or de-encapsulating something previously added so it can read the data. Each of these additions and subtractions is governed by the protocols set within each layer. A perfect network can only exist if these protocols properly govern data transmission, allowing for communication between each layer.
Real-World Applications of the OSI Model
There’s a reason why the OSI model in computer network study is often called a “reference” model – though important, it was quickly replaced with other models. As a result, you’ll rarely see the OSI model used as a way to connect devices, with TCP/IP being far more popular. Still, there are several practical applications for the OSI model.
Network Troubleshooting and Diagnostics
Given that some modern computer networks are unfathomably complex, picking out a single error that messes up the whole communication process can feel like navigating a minefield. Every wrong step causes something else to blow up, leading to more problems than you solve. The OSI model’s layered approach offers a way to break down the different aspects of a network to make it easier to identify problems.
Network Design and Implementation
Though the OSI model has few practical purposes, as a theoretical model it’s often seen as the basis for all networking concepts that came after. That makes it an ideal teaching tool for showcasing how networks are designed and implemented. Some even refer to the model when creating networks using other models, with the layered approach helping understand complex networks.
Enhancing Network Security
The concept of encapsulation and de-encapsulation comes to the fore again here (remember – encryption), as this concept shows us that it’s dangerous to allow a data packet to move through a network with no interactions. The OSI model shows how altering that packet as it goes on its journey makes it easier to protect data from unwanted eyes.
Limitations and Criticisms of the OSI Model
Despite its many uses as a teaching tool, the OSI model in computer network has limitations that are the reasons why it sees few practical applications:
- Complexity – As valuable as the layered approach may be to teaching networks, it’s often too complex to execute in practice.
- Overlap – The very flexibility that makes OSI great for people who want more control over their networks can come back to bite the model. The failure to implement proper controls and protocols can lead to overlap, as can the layered approach itself. Each of the computer network layers needs the others to work.
- The Existence of Alternatives – The OSI model walked so other models could run, establishing many fundamental networking concepts that other models executed better in practical terms. Again, the massive network known as the internet is a great example, as it uses the TCP/IP model to reduce complexity and more effectively transmit data.
Use the OSI Reference Model in Computer Network Applications
Though it has little practical application in today’s world, the OSI model in computer network terms is a theoretical model that played a crucial role in establishing many of the “rules” of networking still used today. Its importance is still recognized by the fact that many computing courses use the OSI model to teach the fundamentals of networks.
Think of learning about the OSI model as being similar to laying the foundations for a house. You’ll get to grips with the basic concepts of how networks work, allowing you to build up your knowledge by incorporating both current networking technology and future advancements to become a networking specialist.
-
From the same author
Read the articleAs computing technology evolved and the concept of linking multiple computers together into a “network” that could share data came into being, it was clear that a model was needed to define and enable those connections. Enter the OSI model in computer network idea.
This model allows various devices and software to “communicate” with one another by creating a set of universal rules and functions. Let’s dig into what the model entails.
History of the OSI Model
In the late 1970s, the continued development of computerized technology saw many companies start to introduce their own systems. These systems stood alone from others. For example, a computer at Retailer A has no way to communicate with a computer at Retailer B, with neither computer being able to communicate with the various vendors and other organizations within the retail supply chain.
Clearly, some way of connecting these standalone systems was needed, leading to researchers from France, the U.S., and the U.K. splitting into two groups – The International Organization for Standardization and the International Telegraph and Telephone Consultive Committee.
In 1983, these two groups merged their work to create “The Basic Reference Model for Open Systems Interconnection (OSI).” This model established industry standards for communication between networked devices, though the path to OSI’s implementation wasn’t as clear as it could have been. The 1980s and 1990s saw the introduction of another model – The TCP IP model – which competed against the OSI model for supremacy. TCP/IP gained so much traction that it became the cornerstone model for the then-budding internet, leading to the OSI model in computer network applications falling out of favor in many sectors. Despite this, the OSI model is still a valuable reference point for students who want to learn more about networking and still have some practical uses in industry.
The OSI Reference Model
The OSI model works by splitting the concept of computers communicating with one another into seven computer network layers (defined below), each offering standardized rules for its specific function. During the rise of the OSI model, these layers worked in concert, allowing systems to communicate as long as they followed the rules.
Though the OSI model in computer network applications has fallen out of favor on a practical level, it still offers several benefits:
- The OSI model is perfect for teaching network architecture because it defines how computers communicate.
- OSI is a layered model, with separation between each layer, so one layer doesn’t affect the operation of any other.
- The OSI model offers flexibility because of the distinctions it makes between layers, with users being able to replace protocols in any layer without worrying about how they’ll impact the other layers.
The 7 Layers of the OSI Model
The OSI reference model in computer network teaching is a lot like an onion. It has several layers, each standing alone but each needing to be peeled back to get a result. But where peeling back the layers of an onion gets you a tasty ingredient or treat, peeling them back in the OSI model delivers a better understanding of networking and the protocols that lie behind it.
Each of these seven layers serves a different function.
Layer 1: Physical Layer
Sitting at the lowest level of the OSI model, the physical layer is all about the hows and wherefores of transmitting electrical signals from one device to another. Think of it as the protocols needed for the pins, cables, voltages, and every other component of a physical device if said device wants to communicate with another that uses the OSI model.
Layer 2: Data Link Layer
With the physical layer in place, the challenge shifts to transmitting data between devices. The data layer defines how node-to-node transfer occurs, allowing for the packaging of data into “frames” and the correction of errors that may happen in the physical layer.
The data layer has two “sub-layers” of its own:
- MAC – Media Access Controls that offer multiplexing and flow control to govern a device’s transmissions over an OSI network.
- LLC – Logical Link Controls that offer error control over the physical media (i.e., the devices) used to transmit data across a connection.
Layer 3: Network Layer
The network layer is like an intermediary between devices, as it accepts “frames” from the data layer and sends them on their way to their intended destination. Think of this layer as the postal service of the OSI model in computer network applications.
Layer 4: Transport Layer
If the network layer is a delivery person, the transport layer is the van that the delivery person uses to carry their parcels (i.e., data packets) between addresses. This layer regulates the sequencing, sizing, and transferring of data between hosts and systems. TCP (Transmission Control Protocol) is a good example of a transport layer in practical applications.
Layer 5: Session Layer
When one device wants to communicate with another, it sets up a “session” in which the communication takes place, similar to how your boss may schedule a meeting with you when they want to talk. The session layer regulates how the connections between machines are set up and managed, in addition to providing authorization controls to ensure no unwanted devices can interrupt or “listen in” on the session.
Layer 6: Presentation Layer
Presentation matters when sending data from one system to another. The presentation layer “pretties up” data by formatting and translating it into a syntax that the recipient’s application accepts. Encryption and decryption is a perfect example, as a data packet can be encrypted to be unreadable to anybody who intercepts it, only to be decrypted via the presentation layer so the intended recipient can see what the data packet contains.
Layer 7: Application Layer
The application layer is a front end through which the end user can interact with everything that’s going on behind the scenes in the network. It’s usually a piece of software that puts a user-friendly face on a network. For instance, the Google Chrome web browser is an application layer for the entire network of connections that make up the internet.
Interactions Between OSI Layers
Though each of the OSI layers in computer networks is independent (lending to the flexibility mentioned earlier), they must also interact with one another to make the network functional.
We see this most obviously in the data encapsulation and de-encapsulation that occurs in the model. Encapsulation is the process of adding information to a data packet as it travels, with de-encapsulation being the method used to remove that data added data so the end user can read what was originally sent. The previously mentioned encryption and decryption of data is a good example.
That process of encapsulation and de-encapsulation defines how the OSI model works. Each layer adds its own little “flavor” to the transmitted data packet, with each subsequent layer either adding something new or de-encapsulating something previously added so it can read the data. Each of these additions and subtractions is governed by the protocols set within each layer. A perfect network can only exist if these protocols properly govern data transmission, allowing for communication between each layer.
Real-World Applications of the OSI Model
There’s a reason why the OSI model in computer network study is often called a “reference” model – though important, it was quickly replaced with other models. As a result, you’ll rarely see the OSI model used as a way to connect devices, with TCP/IP being far more popular. Still, there are several practical applications for the OSI model.
Network Troubleshooting and Diagnostics
Given that some modern computer networks are unfathomably complex, picking out a single error that messes up the whole communication process can feel like navigating a minefield. Every wrong step causes something else to blow up, leading to more problems than you solve. The OSI model’s layered approach offers a way to break down the different aspects of a network to make it easier to identify problems.
Network Design and Implementation
Though the OSI model has few practical purposes, as a theoretical model it’s often seen as the basis for all networking concepts that came after. That makes it an ideal teaching tool for showcasing how networks are designed and implemented. Some even refer to the model when creating networks using other models, with the layered approach helping understand complex networks.
Enhancing Network Security
The concept of encapsulation and de-encapsulation comes to the fore again here (remember – encryption), as this concept shows us that it’s dangerous to allow a data packet to move through a network with no interactions. The OSI model shows how altering that packet as it goes on its journey makes it easier to protect data from unwanted eyes.
Limitations and Criticisms of the OSI Model
Despite its many uses as a teaching tool, the OSI model in computer network has limitations that are the reasons why it sees few practical applications:
- Complexity – As valuable as the layered approach may be to teaching networks, it’s often too complex to execute in practice.
- Overlap – The very flexibility that makes OSI great for people who want more control over their networks can come back to bite the model. The failure to implement proper controls and protocols can lead to overlap, as can the layered approach itself. Each of the computer network layers needs the others to work.
- The Existence of Alternatives – The OSI model walked so other models could run, establishing many fundamental networking concepts that other models executed better in practical terms. Again, the massive network known as the internet is a great example, as it uses the TCP/IP model to reduce complexity and more effectively transmit data.
Use the OSI Reference Model in Computer Network Applications
Though it has little practical application in today’s world, the OSI model in computer network terms is a theoretical model that played a crucial role in establishing many of the “rules” of networking still used today. Its importance is still recognized by the fact that many computing courses use the OSI model to teach the fundamentals of networks.
Think of learning about the OSI model as being similar to laying the foundations for a house. You’ll get to grips with the basic concepts of how networks work, allowing you to build up your knowledge by incorporating both current networking technology and future advancements to become a networking specialist.
-
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Bring talented tech experts together, set them a challenge, and give them a deadline. Then, let them loose and watch the magic happen. That, in a nutshell, is what hackathons are all about. They’re proven to be among the most productive tech events when it comes to solving problems and accelerating innovation.
What Is a Hackathon?
Put simply, a hackathon is a short-term event – often lasting just a couple of days, or sometimes even only a matter of hours – where tech experts come together to solve a specific problem or come up with ideas based on a central theme or topic. As an example, teams might be tasked with discovering a new way to use AI in marketing or to create an app aimed at improving student life.
The term combines the words “hack” and “marathon,” due to how participants (hackers or programmers) are encouraged to work around-the-clock to create a prototype, proof-of-concept, or new solution. It’s similar to how marathon runners are encouraged to keep running, putting their skills and endurance to the test in a race to the finish line.
The Benefits of Hackathons
Hackathons provide value both for the companies that organize them and the people who take part. Companies can use them to quickly discover new ideas or overcome challenges, for example, while participants can enjoy testing their skills, innovating, networking, and working either alone or as part of a larger team.
Benefits for Companies and Sponsors
Many of the world’s biggest brands have come to rely on hackathons as ways to drive innovation and uncover new products, services, and opportunities. Meta, for example, the brand behind Facebook, has organized dozens of hackathons, some of which have led to the development of well-known Facebook features, like the “Like” button. Here’s how hackathons help companies:
- Accelerate Innovation: In fast-moving fields like technology, companies can’t always afford to spend months or years working on new products or features. They need to be able to solve problems quickly, and hackathons create the necessary conditions to deliver rapid success.
- Employee Development: Leading companies like Meta have started to use annual hackathons as a way to not only test their workforce’s skills but to give employees opportunities to push themselves and broaden their skill sets.
- Internal Networking: Hackathons also double up as networking events. They give employees from different teams, departments, or branches the chance to work with and learn from one another. This, in turn, can promote or reinforce team-oriented work cultures.
- Talent Spotting: Talents sometimes go unnoticed, but hackathons give your workforce’s hidden gems a chance to shine. They’re terrific opportunities to see who your best problem solvers and most creative thinkers at.
- Improving Reputation: Organizing regular hackathons helps set companies apart from their competitors, demonstrating their commitment to innovation and their willingness to embrace new ideas. If you want your brand to seem more forward-thinking and innovative, embracing hackathons is a great way to go about it.
Benefits for Participants
The hackers, developers, students, engineers, and other people who take part in hackathons arguably enjoy even bigger and better benefits than the businesses behind them. These events are often invaluable when it comes to upskilling, networking, and growing, both personally and professionally. Here are some of the main benefits for participants, explained:
- Learning and Improvement: Hackathons are golden opportunities for participants to gain knowledge and skills. They essentially force people to work together, sharing ideas, contributing to the collective, and pushing their own boundaries in pursuit of a common goal.
- Networking: While some hackathons are purely internal, others bring together different teams or groups of people from different schools, businesses, and places around the world. This can be wonderful for forming connections with like-minded individuals.
- Sense of Pride: Everyone feels a sense of pride after accomplishing a project or achieving a goal, but this often comes at the end of weeks or months of effort. With hackathons, participants can enjoy that same satisfying feeling after just a few hours or a couple of days of hard work.
- Testing Oneself: A hackathon is an amazing chance to put one’s skills to the test and see what one is truly capable of when given a set goal to aim for and a deadline to meet. Many participants are surprised to see how well they respond to these conditions.
- Boosting Skills: Hackathons provide the necessary conditions to hone and improve a range of core soft skills, such as teamwork, communication, problem-solving, organization, and punctuality. By the end, participants often emerge with more confidence in their abilities.
Hackathons at OPIT
The Open Institute of Technology (OPIT) understands the unique value of hackathons and has played its part in sponsoring these kinds of events in the past. OPIT was one of the sponsors behind ESCPHackathon 6, for example, which involved 120 students given AI-related tasks, with mentorship and guidance from senior professionals and developers from established brands along the way.
Marco Fediuc, one of the participants, summed up the mood in his comments:
“The hackathon was a truly rewarding experience. I had the pleasure of meeting OPIT classmates and staff and getting to know them better, the chance to collaborate with brilliant minds, and the opportunity to take part in an exciting and fun event.
“Participating turned out to be very useful because I had the chance to work in a fast-paced, competitive environment, and it taught me what it means to stay calm and perform under pressure… To prospective Computer Science students, should a similar opportunity arise, I can clearly say: Don’t underestimate yourselves!”
The new year will also see the arrival of OPIT Hackathon 2026, giving more students the chance to test their skills, broaden their networks, and enjoy the one-of-a-kind experiences that these events never fail to deliver. This event is scheduled to be held February 13-15, 2026, and is open to all OPIT Bachelor’s and Master’s students, along with recent graduates. Interested parties have until February 1 to register.
The Open Institute of Technology (OPIT) recently held its first-ever career fair to showcase its wide array of career education options and services. Representatives from numerous high-profile international companies were in attendance, and students enjoyed unprecedented opportunities to connect with business leaders, expand their professional networks, and pave the way for success in their future careers.
Here’s a look back at the event and how it ties into OPIT’s diverse scope of career services.
Introducing OPIT
For those who aren’t yet familiar, OPIT is an EU-accredited Higher Education Institution, offering online degrees in technological fields such as computer science, data science, artificial intelligence, cybersecurity, and digital business. Aimed at making high-level tech education accessible to all, OPIT has assembled a stellar team of tutors and experts to train the tech leaders of tomorrow.
The First OPIT Career Fair
OPIT’s first career fair was held on November 19 and 20. And as with OPIT’s lectures, it was an exclusively online event, which ensured that every attendee had equal access to key lectures and information. Interested potential students from all over the world were able to enjoy the same great experience, demonstrating a core principle that OPIT has championed from the very start – the principles of accessibility and the power of virtual learning.
More than a dozen leading international companies took part in the event, with the full guest list including representatives from:
- Deloitte
- Dylog Hitech
- EDIST Engineering Srl
- Tinexta Cyber
- Datapizza
- RWS Group
- WE GRELE FRANCE
- Avatar Investments
- Planet Farms
- Coolshop
- Hoist Finance Italia
- Gruppo Buffetti S.p.A
- Nesperia Group
- Fusion AI Labs
- Intesi Group
- Reply
- Mindsight Ventures
This was a fascinating mix of established enterprises and emerging players. Deloitte, for example, is one of the largest professional services networks in the world in terms of both revenue and number of employees. Mindsight Ventures, meanwhile, is a newer but rapidly emerging name in the fields of AI and business intelligence.
The Response
The first OPIT career fair was a success, with many students in attendance expressing their joy at being able to connect with such a strong lineup of prospective employers.
OPIT Founder and Director Riccardo Ocleppo had this to say:
“I often say internally that our connection with companies – through masterclasses, thesis and capstone projects, and career opportunities – is the ‘cherry on the cake’ of the OPIT experience!
“It’s also a core part of our mission: making higher education more practical, more connected, and more aligned with what happens in the real world.
“Our first Career Fair says a lot about our commitment to building an end-to-end learning and professional growth experience for our community of students.
“Thank you to the Student and Career Services team, and to Stefania Tabi for making this possible.”
Representatives from some of the companies that attended also shared positive impressions of the event. A representative from Nesperia Group, for example, said:
“Nesperia Group would like to thank OPIT for the warm welcome we received during the OPIT Career Day. We were pleased to be part of the event because we met many talented young professionals. Their curiosity and their professional attitude really impressed us, and it’s clear that OPIT is doing an excellent job supporting their growth. We really believe that events like these are important because they can create a strong connection between companies and future professionals.”
The Future
Given the enormous success of the first OPIT career fair, it’s highly likely that students will be able to enjoy more events like this in the years to come. OPIT is clearly committed to making the most of its strong business connections and remarkable network to provide opportunities for growth, development, and employment, bringing students and businesses together.
Future events will continue to allow students to connect with some of the biggest businesses in the world, along with emerging names in the most exciting and innovative tech fields. This should allow OPIT graduates to enter the working world with strong networks and firm connections already established. That, in turn, should make it easier for them to access and enjoy a wealth of beneficial professional opportunities.
Given that OPIT also has partnerships in place with numerous other leading organizations, like Hype, AWS, and Accenture, the number and variety of the companies potentially making appearances at career fairs in the future should no doubt increase dramatically.
Other Career Services at OPIT
The career fair is just one of many ways in which OPIT leverages its company connections and offers professional opportunities and career support to its students. Other key career services include:
- Career Coaching: Students are able to schedule one-on-one sessions with their own mentors and career advisors. They can receive feedback on their resumes, practice and improve their interview skills, or work on clear action plans that align with their exact professional goals.
- Resource Hub: The OPIT Resource Hub is jam-packed with helpful guides and other resources to help students plan out and take smart steps in their professional endeavors. With detailed insights and practical tips, it can help tech graduates get off to the best possible start.
- Career Events: The career fair is only one of several planned career-related events organized by OPIT. Other events are planned to give students the chance to learn from and engage with industry experts and leading tech firms, with workshops, career skills days, and more.
- Internships: OPIT continues to support students after graduation, offering internship opportunities with leading tech firms around the world. These internships are invaluable for gaining experience and forging connections, setting graduates up for future success.
- Peer Mentoring: OPIT also offers a peer mentoring program in which existing students can team up with OPIT alumni to enjoy the benefits of their experience and unique insights.
These services – combined with the recent career day – clearly demonstrate OPIT’s commitment to not merely educating the tech leaders of the future, but also to supporting their personal and professional development beyond the field of education, making it easier for them to enter the working world with strong connections and unrivaled opportunities.
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