Well, one of the things that we need to discuss is physical layer technologies.
And you might think, well, wait a minute, Anthony, the physical layer is just like the cable or
the radio spectrum that is being used in wireless.
But no, there's a little more to discuss here than that.
First of all, understand that when you talk about the physical layer of the OSA model, you're talking
about the electrical and physical specifications.
And there's a word I want you to know here called modulation.
Modulation is all about converting the bits that are going to be carrying the data to the exact method
that's required by the physical medium.
That's going to be very different from physical medium to physical medium, as you might guess.
How the modulation is going to work is going to really vary if we're dealing with something like copper
versus fiber optic versus something like WiFi.
Now the physical layer technologies and specifications are going to get so specific as to the layout
of pins that might be needed in the connector.
Voltage is the specific cable specifications.
One of the things to remember with cable, especially in the area of Ethernet, is that there is a huge
number of variations and each variation is going to have different speeds, different maximum distances
and even different potential issues when it comes to interference.
Also is part of the physical layer is specifications that the host bus or network interface cards are
going to need.
Remember, the host bus adapter is a component that you would typically find in a SAN or storage area
network and the network interface card is typically found in the Ethernet environment.
There's even adapters now that are called converged network adapters, and these seniors have the ability
to do both.
They can function as host bus adapters for the San or Knicks for the LAN simultaneously.
The Layer one technologies that I've already rattled off are things like copper radio wave technologies
for Wi-Fi.
And in the world of fiber, remember, there's single mode fiber and multimode fiber.
The difference, remember, is that single mode fiber is going to be using one wavelength for the data
and multimode fiber is going to be using multiple wavelengths for multiple streams of data.
And again, in the world of fiber, just like in the world of Ethernet and copper and remember, Ethernet
can run over copper or single mode fiber or multimode fiber.
So Ethernet is a very flexible technology as far as the physical layer goes.
But one thing to keep in mind is that just like with copper cabling, the fiber optic cabling, it's
going to have very, very intense specifications, not only on how far the signal can go before it needs
to be dealt with, but also things like are in the world of fiber.
There's how much you can bend that media.
So it's not going to be, you know, my goodness, if you look around my office, I'm sure you can find
an Ethernet cable or two that is almost completely at a 45 degree angle and probably crimped by one
of my books or desks or something.
So, you know, those kinds of bends and that kind of damage really to the cable can't be done, obviously,
in optical environments where you are dealing with tiny, tiny strands of glass.
It really is amazing is that when you think about everything that has to go right, when it comes to
sending data from one workstation to another, if you consider it right down to this physical layer.
So I hope you found that interesting.
You know, whenever you bring up the physical layer, two students are like, well, this is going to
be really boring because what is there to talk about at the physical layer?
We're going to be hacking at a layer much higher than the physical layer.
Unless, of course, you know, the physical layer is something we are literally breaking into.
But anyways, I digress a bit.
The physical layer is important, and I'm super glad you watched this video.