OSI Typological Analogy

 Clothes And IT - Layering Them On

When it comes to learning all those tricky little details in the world of computing and technology, most of us haven’t the IT abstractions demystified in such a way, that we can pragmatically apply what we know to help us build complex data applications and network transmissions.

And for the beginner and lightly seasoned developer… THAT’S OK… 

…there are layers upon layers of what can seem like sorcery to the average programmer who hasn’t yet dared to delve into the naked truth underneath all those layers of…shall we call them clothes?

The hierarchal and structural levels of both the mechanics and machinery involved in computing, as well as the supporting software protocols most view and reference simplistically, are actually quite complex, with some of the most advanced concepts of mathematics and computational theory observed and applied, making the machines and machine-like electronics most of us use daily, true mechanical marvels, to say the least.  

Let’s undress a little of it…shall we. 

The layered schema of what is known as the Open Systems Interconnection Model, or OSI for short, is a typological representation of the networking protocols used to receive, process, display, and share our computational data with the help of easy to use “windows” and graphical user interfaces that elegantly dress complex processes. 

So OMNITEKK… just what is this OSI typology…

…Let us demystify things a little with a warehouse packaging analogy shall we…

 

But first, my friend, I must provide those foundational concepts that help give us an overview of the typology first, so here goes.

The hierarchal typology is comprised of 7 layers of interconnected or networking protocols that essentially serve different functions, while also acting as “checks and balances” to those contiguous protocols most closely connected to it, to ensure that each layer or level within the typology maintains adherence to specific structural design methods.

A pictorial of the layer nomenclature or names are as follows - 

And now for our explanatory analogy highlight….

Let’s say we are workers at fictious warehouse company EFGlobal, who receives, sorts, routes, and delivers packages to their assigned destinations using the OSI typological designations. 

They manage to accomplish this within the context of the 7 layer Typology in the following ways -

Application Layer

The Application Layer or Human Machine Interface Layer (HMI) is designed to provide a layer of abstraction that seamlessly allows end users to interact with the computer without having to completely know what’s happening outside of what they see - or better phrased, outside of the application visuals. 

This layer is where most “window based” software applications are presented to the end-user. 

In our warehouse, this layer represents the packaging of all contents received, routed and shipped. For workers in our warehouse to successfully ship packages to their final destinations, we need not know what’s in them, we simply need the geolocation routing data, expected package receipt time, and who should be receiving the packages so that we know the who, where, and when in the 5 W’s concept of Who, What, When, Where, and Why.

Presentation Layer

Like a good circus show, before the audience can view the act, it has to be rehearsed so as to ensure its final presentation meets praiseworthy standards. This is precisely what the presentation layer does.

It acts as an intermediary between the application layer visuals and those attributes and protocols that have to be perfected or (presented) to ensure the end-user HMI is constructed as it should be.

Likewise, this layer also enforces encryption protocols and usable interface formats.

We aren’t interested in circus acts though are we…for all intents and purposes we don’t work at the circus, we’re warehouse workers. So, let’s visualize our warehouse process shall we... I digress…I digress.

In our warehouse, this layer is responsible for ensuring that all packages arrive in the best fashion possible. Who wants to anxiously await a package, only to find broken contents inside when they open it…no one!

So, in our warehouse, we ensure that all our packages are received as they should be. We use protective bubble wrap to protect package contents, we use tape to protectively seal the packages so the contents don’t come out and we might even add special stickers so that our delivery workers know to handle certain packages lightly. 

Session Layer

Sessions are the chronicles of reference where all communication between interfaces are maintained…so time is of the essence here…literally! 

The session layer maintains communication between nodes, user-computer interfaces and networked connections between them. 

We might think of this layer as our warehouse manager of operations communications, as it synchronizes and orchestrates all communications occurring between end-user applications so that we know when our packages will be sent to or received by end users. 

At this layer, we also keep a recorded account of our package locality information, so that we know where they are, so we don’t lose them.

Transport Layer

This layer is responsible for delivering messages between network and host. If we think of nodes or computers on a network, then the transport layer is responsible for directing the traversal of information between them. 

At this layer, specific protocols used to communicate package information are also enforced and observed so as to prevent data loss and data collisions.

Analogically speaking…as we move packages through our warehouse, at this layer, we determine how the packages will travel. 

For instance, will they travel by bus, car, plane or train. 

There are also a few checks performed, to ensure that all end-user addresses or destinations are in fact valid so that packages are delivered without fail. 

Network Layer

The network layer determines which physical or actual path a node on a network will take to deliver a communication between them.

Just as there are quite a few paths we can travel to reach our destination we have to choose one, and most of us (or at least those of us who mightn’t choose to meander as we travel to enjoy the scenery) choose the shortest route possible. This is the tasked function of the network layer.

Back at the warehouse, once our guys have figured out how those packages are going to travel, they should probably decide on a mapped travel route to get them there…shouldn’t they?

DataLink Layer

The datalink layer is the intermediary between point-to-point networking hardware or nodes on both end-user networks, such that the tangible peripherals that catalyze or facilitate the communication between all other layers on the network, and likewise their subsequent communications, occur as designed without fail.

In order for our warehouse operation to successfully deliver packages to all those lovely patrons, all other communicative processes must be properly coordinated so that we have happy consumers.

Those working in the warehouse must communicate within the facility so that packages are received, sorted, assigned a destination and route, and finally expedited to their destinations. 

Likewise, the base warehouse workers must also have a means to communicate with the transportation folks while packages are in transit, especially in the event that some sort of anomaly or problem occurs.

So, the entire family of warehouse workers procure the necessary communication channels, ensuring all package deliveries are routed as they should be.

After all, at EFGlobal we take pride in our means of ensuring our package delivery processes are the best in the business…And oh yeah…the folks here marvel at the chance to make consumers happy. 

Physical Layer

The physical layer comprises all the tangible components within the computing ecosystem that allow for all other communication between nodes, whether on a closed or unitary system or as a cluster of networked nodes to occur seamlessly and contiguously.

It includes all networking peripherals and hardware on the network alike, that make the communication channels necessary so that data is transferred across physical media, such as ethernet cables, routers or other tangible networking devices.

Our package delivery warehouse system has to have not only the manpower to coordinate the corporate processes that prepare our packages for delivery, but it also needs the tools to accomplish it all.

Let’s see here…There’s the warehouse equipment, the vehicles used for transportation of the packages, and likewise, the communication devices that allow all workers to communicate with each other, such as radio devices etc.  

Have The Clothes Come Off...

Omnitekk sincerely hopes you have a better sense of how computers help other computers and those natively networked software applications, communicate across a network.

If my anology helped you figure out a few things... Network Typology Served...

Until our next IT Adventure my friends.....Omnitekk says - Enjoy.