Past to present: Exploring and analyzing the history of PON development & evolution

In this Vitex Talks episode, we’ll break down the different types of PON (Passive Optical Network) setups and the corresponding acronyms used in the fiber optics industry. The video aims to help viewers understand the progression of PON bandwidth speeds and the different standard bodies involved, more specifically ITU and IEEE.

Listen to the article

Watch the video


(0:00-0:15) Intro
(0:16-0:27) “What is B-PON, E-PON and G-PON?”
(0:28-1:16) PON acronyms
(1:17-1:37) A-PON
(1:38-1:59) B-PON
(2:00-2:32) G-PON
(2:33-3:05) E-PON
(3:06-3:28) XG-PON
(3:29-3:37) XGS-PON
(3:38-4:08) NG-PON2
(4:09-4:29) 10 G-EPON
(4:30-6:51) 10G comparison
(6:52-7:25) Conclusion

Read the transcript


Hey everybody, this is Craig at Vitex again and today we’re answering some of your questions. So today we’re going to shine a light on some PON questions.

“What is B-PON, E-PON and G-PON?”

We have a question from Matt who works for a broadband services company. What do the terms B-PON, E-PON and G-PON mean? Can you talk us through these acronyms?

PON acronyms

Thank you so much for that question. Yeah, it was definitely an awesome one and I totally agree with you. There are a lot of acronyms in PON setups, but we’re here to help you out with this PON alphabet soup. When you work with us, no problem. Easy peasy, lemon squeezy as I like to say.

So, let’s just go through our alphabet and give you a better understanding. What we’re going to do is we’re going to look at these PON components mostly based on the different types of standard bodies. There are two main standard bodies when it comes to PON. There’s the ITU and the IEEE. So just to get a little brief history about it, of course when we started, we had much slower bandwidths, down to 155 Mb/s and you can see as time goes on, we get larger bandwidths and we’re up now to 10 Gb/s. So, let’s see how this kind of developed.


So, when we first started, we were at A-PON, which is an ATM PON. This was the first iteration of PON, and it had 155 Mb/s-down and it had 155 Mb/s-up. But of course, more applications came out [and] more fiber to the home. There was a need for greater speed.


This quickly developed into our next letter, which is our B-PON. And here we increased our downlink speed, but our uplink speed remained relatively the same. But this still wasn’t enough for users. They still wanted more. [Then,] what we started is pushing the boundaries past Mb/s into Gb/s.


And then the ITU standard came out with the G-PON. So, I know you’re expecting C—right—“ABC”. This only really makes sense if you know Greek alphabet, right? Alpha, beta, gamma, but that’s not really where it comes from. Here the G refers to Gigabit speeds. You can see we’re breaking one Gb/s and we’re getting in the standard as high as 2.5-down and 1.25-up. At the same time, the IEEE is getting in the mix here. And they said, “Okay, well what kind of speeds can we offer that are around the same rate?”


And here comes our next letter, which makes total sense in sequential order, is the E-PON. But here E stands for Ethernet. And we all know IEEE from a lot of Ethernet standards. It makes sense that they’re focusing on an Ethernet type of frame and protocol. Next as we develop past 1 Gb/s, we make it into our 10 Gb/s rates. So, the ITU has a couple standards actually that comes out over a period of time around this.


The first one is our X Gb/s, right? So, what does that mean? … This is actually saying, well, we have letters. Let’s throw some numbers in. But this is a Roman numeral X. This means 10 Gb/s…this is the first time we’re breaking 10 Gb/s on the downlink.


But we were not in a symmetrical 10 Gb/s-up, 10 Gb/s-down. After that came our XGS-PON, which balanced out our rates in the uplink and the downlink. After that, we said, “Okay, well, let’s leave the numbering and go back to lettering.”


We threw in NG-PON2. But this is our next generation, right? Everything comes out big. It’s always next gen. So that’s when we move into our NG. Here the objective was to add this capability of bi-directional. Using different wavelengths so that you can use a G-PON, an XG-PON. You can use all this stuff in your network in the same way.


So, what was going on with the good old IEEE in this situation? Well, they liked numbers, so they stayed with that. And they just added a 10. So now they’re also at 10 Gb/s. So, but how do these two 10 Gb/s kind of stack up? So, let’s jump over here and see how everything shakes out.

10G comparison

We’re going to do a quick 10 Gb/s comparison. I’ve selected the XGS-PON and the 10 G-PON. I know some of you are thinking this isn’t probably the best comparison to make because they didn’t come out at the same time. So, leave me a comment and let me know if I should really be comparing them to something else that’s more along the time of when the standards came out.

But just because these have like a really good overlap on the different features to them and how they operate, we can see their downlink/uplink is the same. They operate in the same wavelength. You know, we see some differences such as modulation, the NRZ, or an Ethernet modulation on the other side. And then the next two major differences look at how much can be the, can the splitting go on?

The ITU standard allows up to 256 while IEEE is at 64. And another area is the maximum reach. We see 40 kilometers, it’s twice as much as the size. Both of these will require a FEC (forward error correction). And I know some of you are like, “Oh great, that’s another acronym.” You know, if you have a question about that, go ahead and send it out. We can answer it as well.

But all of these components in the network, a lot of these transceivers, we can totally support you from Vitex. We have all of these in our product line. Check out our website or give us a call here at our New Jersey location. We’ll be happy to explain more of what this whole alphabet soup is or set you up with the right transceiver in your PON network.

So, we see that a lot of these are 10 Gb/s, but what happens after that? Do we just stop there? Do we go further? We’ll talk about this more in another episode. But right now, I’m just giving you a sneak peek. So, everybody’s heard of this WDM. And if you haven’t, let me know. So here we bring in this concept of, “Oh, we’re using different wavelengths in light.” What do you think is going to happen when we’re adding all of these different wavelengths in here, or maybe not one, into this system? Can we add one, two? Can we bring up to eight? Where’s the limit of how many we can add? Let me know what you think. If you think this is going to be useful and how it’s going to play out in the standards, or if you already know that it would be awesome just for you to put it in there because some of you know the answer to this question already.


So, keep those questions coming. And remember, if your question gets selected for one of our videos, I’m going to send you a cup of coffee to enjoy. So, until next time, we’ll see you then.

Group working together

Subscribe and stay informed

Your job is easier with a fiber optic expert for a friend.