How does the OSI Model apply to us??

The Open Systems Interconnection model is a model that allows the IT community to understand how our networks operate and separates the model into seven layers.

Layer 7 is the Applications layer.

This is where we all operate in our daily lives. We open up our preferred internet browser (i.e. Chrome, Internet Explorer, etc.) and start to browse the internet or research, etc. Another example would be the use of Skype or Microsoft word. We use these applications on a daily basis.

Layer 6 is the Presentation layer.

We don’t see this layer as the presentation layer is what the operating systems run on. This layer translates the data, encrypts it, and decrypts it between the network and application. So it’s the middle man between the application you the user uses and what that application is running on.

Layer 5 is the Session layer.

The session layer is something we don’t as users realize we’re utilizing. One example of this layer in use is when we have multiple web pages open on a single browser. Also it’s the connection and communication between two computers. An example is when we as users log on to our browsers to access our bank accounts. We open up the web page, go to the website and then when we log into our bank account that is the connection between two computers. Or in that example a computer and an offsite server with the bank that’s allowing you to view your accounts.

Layer 4 is the Transport layer.

Definitely this layer we never know or think about in our daily activities at work. This is why we have IT teams and engineers that know how this works in the OSI model. The best way to describe this layer is that it ensures the reliable delivery of data. Sometimes the data is broken up into segments/labels  and then reassembled at the user level.

Layer 3 is the Network layer.

Now we’re having fun here. This is where our routers live at the office. IP addresses are translated with the messages we all send and receive to their host destination which would be our intended recipient. . Layer 3 allows data transfer between networks and pushes your data across the network. Data comes in many forms from emails, sending files, watching YouTube, to holding a video conference. If we have a slow network or a congested network then we’ll start to experience slow speeds, choppy video streams, buffering and terrible underwater sounding phone calls. Can’t have it.

Layer 2 is the Data Link layer.

This is where our switches live. When we bring fiber to a building we install a Layer 2 device, a switch in the building. Layer 2 allows a connection between two network nodes. A point to point. If we need to connect two or more locations together we do this with a point to point layer 2 service. The best way to run bandwidth hungry applications is to use a layer 2 service as it’ll provide the best quality of service to do so. E.G. Voice services and video communications.

Layer 1 is the Physical layer.

Very simply it’s the actual physical wiring in our offices. It’s the fiber in the ground and installed into a switch. It’s the patch panels in telco rooms, cords under our desks etc.

The next time an issue comes up this is what our IT teams have to deal with to try and find and remedy a problem. Maintaining a network is far more advanced technically that what we deal with daily, but maintaining the network keeps us working and productive. Thus give an IT person a hug the next time you see them as they do a thankless job to keep us up and running daily.

Daniel Macias | Fiber Sales Professional