From the course: CompTIA Network+ (N10-009) Cert Prep

Transceivers

From the course: CompTIA Network+ (N10-009) Cert Prep

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Transceivers

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- The big challenge that you run into when you start using fiber ethernet is that you don't have one physical standard when it comes to connection. When we're using copper, it's pretty much always RJ45s. So I don't care if it's 10 base T or one gig, you're still going to be using that same type of physical connection. Now, with fiber, they don't specify that, and it's a smart idea because there's a lot of different ways to make fiber connections. We've got an entire episode that goes over things like ST and SC and LC and MTRJ type connectors. But imagine you're in a situation where you're buying some new switches, and if we were fixed on only one type of connector, we would have a real problem because I would have to build a switch that would be one version of switch that had ST connectors in it, another switch that had SC connectors in it, and another switch that had LC, and all this, the exact same switch. So to get around this problem, the guys who make switches got together, Cisco and Netgear, and all these people, and they sat around in a room, and first of all, they said, "Okay, we all hate each other. We're all competitors. However, we got a problem when we're using fiber optic ethernet, and what we need to do is come up with some type of little interchangeable module that will work in any of our switches," and this is where we come up with the idea of what we call generically MSA. So if everybody has ST connectors, they can have a module that you snap in with ST connectors. If another person has SC connectors, they can take the same switch, they plug in a module with SC connectors. You get the idea? Now, this has been around for quite a long, long time, and there's been, and they're known generically as, these modules are transceivers. I've got a few of them right here. I'm going to take a look at these, and these are pluggable devices that allow you to keep one switch and use any type of fiber connectors you want within that standard. So let's go ahead and get started with this guy right here. This is the first generation of MSA, and this is known as a GBIC. A GCIC, it was designed more for ST and SC connectors, and if you take a look on this older switch I have over here, you'll see it has two GBIC modules. So if I'm running SC, I'll get a GBIC with SC connectors, snap that thing in. Oops! And you'll see I've already got my SC plugged in and working. I could take the same switch, go to somebody who has ST connectors, the round ones, buy a module for STs, and this exact same switch would work over there without us trying to cut off and re-splice a couple of gazillion fiber optic ends. So GBICs were great, but over time, one of the big things that started to happen is we started using these small form-factor types of connectors like LC and MTRJ, and that's where this guy came into being. We call this a small form-factor pluggable, or SFP. Now it's still a transceiver, but the big difference it has over the GBICs is it's designed for these small form-factors. So what I'm going to do, if you take a look on this switch over here, you'll see it's got four SFP ports on here. Now again, I don't even have to use 'em if I don't want to, but in this case, let's say I have an LC connection, I can go ahead and plug that guy in like that. I just happen to have an LC right here, and we've got the SFP up and working. There's an improved version of SFP that looks absolutely identical to this called an SFP+ and you would use that if the switch actually specified for your particular system, what it requires. SFP+ is actually a lot more common than SFP today. Now there is one other type of connector, and I don't have a copy of it, but I got a picture, so let me show this to you real quick. This is a quad pluggable device. Now the QSFP is really designed for more than anything else, you ready? 40 gigabit ethernet, so be aware it is on the exam. So make sure if you see QSFP, you know it's a transceiver that's used for 40 gigabit ethernet. Now there's one more I want to show you. Now if you take a look at this SFP right here, you'll notice it's duplex, and whenever we use fiber optics, we always have duplex. One cable is send and one cable is receive. Now this is multi-mode. We can tell by the orange, and also the fact that I just happen to know this one, but one of the things that you can do, and this is particularly common with single mode fiber optic, is that you can use different colors. Remember single single mode is lasers, so you can use different colors of lasers to send and receive on the same cable, and we call this bidirectional or bidi. And there are very specific, I'm going to show you one right here, transceivers that are designed for this type of connection. So let me plug this guy in, and take a good close look at that. You know, in fact, let me leave the latch down. So if you take a look at this guy, you'll notice that unlike this other one right here, it only has a single connection on there. That's all it needs. What happens here is that on this one, it will send on one color and receive on a different color, and then you'll have, these are almost always sold in pairs 'cause the other one has to send in the opposite color and receive in the opposite color from what this is sending and receiving. But the cool part about these is, if you want to, it only needs a single connection. Now this is duplex 'cause I got it laying around, but you would actually have the ability to use just one piece of fiber. The big benefit over that more than anything else is that it reduces the amount of cabling and it's also probably the next generation in terms of really scary speeds that we'll probably be seeing in the next five to 10 years when it comes to fiber. I love transceivers in the world of fiber optics. If there's one thing I've learned the hard way, and that is cutting off some type of terminator and then changing it to something else can be a real pain. With MSAs and the different types of transceivers, we can come up with really great solutions to take care of almost any type of connectivity scenario we'd run into when it comes to fiber optic.

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