What did the 0 say to the 1? 

“Nice belt!”

Ok, that was bad. But I love to start off a post about data layers with a bad numbers joke. 

Let’s talk about the next layer in our TCP/IP network stack called the Data Link Layer. 

Credit: Google

You probably use wireless Internet access at home, so it might be surprising to hear that traditional cable networks are still the most common option found in the workplace and definitely inside data centers. The protocol most widely used to send data across individual links is known as Ethernet. Ethernet and the data link layer provide a way for software to send and receive data. One of the primary purposes of this layer is to abstract away the need for any other layers to care about the physical layer and what hardware is in use. By dumping this responsibility on the data link layer, the Internet, transport and application layers can all operate the same no matter how the device they’re running on is connected. 

What does this mean exactly?

Well, your web browser, for instance, doesn’t need to know if it’s running on a device connected via a twisted pair or a … Read the rest

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Ok, not that kind of physical. 

Get your mind out of the gutter and back into the TCP/IP model.

Credit: Google

Our physical layer is ALL about moving 1s and 0s from one end of a link to another. It might sound simple, but there’s a lot of very complex math and engineering principles utilized in order to transmit YUGE volumes of data across tiny copper or fiber wires at incredible speeds. 

The “stuff” transmitted along this layer consists of bits. You might remember them from a previous post, but they are essentially the smallest representation of data that a computer can understand. It’s a 1 or a 0. These 1s and 0s make up the frames and packets of data we’ll dig into later. The important thing to understand is that whether you’re streaming a Justin Bieber song, emailing your co-workers, or even using an ATM, you’re really just sending 1s and 0s across the physical layer of the many different networks between you and the server you’re interacting with. 

A typical copper network cable connected to devices on both ends carries a positive electrical charge. The 1s and 0s are sent across the network cables via a process … Read the rest

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In my previous post I talked about some of the devices found within each layer of the TCP/IP and OSI models. 

Now let’s take a closer look at some of them. 

A Hub is a physical layer device that allows connections from many computers at once. 

Credit: Google

Sounds good right? We want each computer on our network to be able to communicate, but there’s a major problem.

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Hubs can lead to something called a Collision Domain, which is a network segment where only one device can communicate at a time. 

If multiple systems try sending data at the same time, the electrical pulses sent across the cable actually interfere with each other and cause systems to have to wait for a quiet period before sending their data again. 

Credit: Google

This is a major reason why you rarely find a hub these days. But look, no offense meant if you have a hub at home. This blog is 100% inclusive of all belief systems.  

A much more common way of connecting many computers is a more sophisticated device called a Network Switch. This was originally known as a switching hub. 

A switch is very similar to a hub … Read the rest

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Trigger warning: this might cause sweaty palms. Remember when you were in middle school science class and you had to memorize the periodic table of elements? 

That’s immediately what I thought of when I first learned about the TCP/IP Five Layer Network Model and the Open Systems Interconnection (OSI) Reference Model. Lots of important data in a table to memorize. But it’s so much more than that. As soon as I got past my fear of an intimidating looking pair of tables and began to see these models for the incredible, clever creations they are, I developed a whole new appreciation. 

Here’s a great overall view of the OSI model:

Credit: David Prasad

The true brilliance of these models has to do with something called abstraction. When something is abstract, we often think it means it is difficult to understand. And when things are difficult to understand they tend to be scary. But, in our case abstraction isn’t difficult to grasp and it’s one of the fundamental concepts of computing, so let’s talk about it for a moment. The traditional definition of abstraction is: a way of hiding the working details of a subsystem, allowing the separation of concerns to facilitate interoperability and platform … Read the rest

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Let’s learn how to solve global warming!

Just kidding.

While we can’t solve any and every problem, there are useful steps we can follow in order to help users as an IT specialist.

If you told your mechanic your car just doesn’t work and your mechanic decided to replace your transmission, you probably wouldn’t go back again. At least I would hope not. Likewise, if you told your doctor you felt sick and she immediately wrote you a prescription for an antibiotic medication without any other information, you probably wouldn’t go back either. 

In the world of IT, knowing how to troubleshoot and solve problems is a lot more effective than trying to memorize the solution to every possible problem…or rely on experience and instinct alone.

Luckily we have a set of tools and best practices we can follow to help us solve common IT issues. Try these out next time you encounter a problem! 

Ask questions & isolate the problem

Problems can’t be solved without first asking the right questions. Maybe if our mechanic asked us something like, “Can you tell me a little bit more about how it’s broken?” Or, “Has there been any damage to it lately … Read the rest

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