A bit about PON. Part 2

Just a quick reminder, folks—I’m not a PON, networking, or fiber optics engineer. Everything I know about this stuff comes straight from my own hands-on experience. I’ll be the first to admit my knowledge is pretty high-level, but hopefully, someone out there finds it useful.
Anyway, let’s pick up where we left off. The main difference between GPON and GEPON is that GPON uses fixed-length frames and synchronized transmission—meaning the OLT sends and receives frames based on its own internal clock. Since these frames have a strictly defined size, any large packet gets chopped up into small pieces and sent in parts. GEPON, on the other hand, is built on top of standard Ethernet, where the timing and size of the transmitted data aren't known in advance. While downstream data from the OLT is filtered by the ONT using an ID, the upstream traffic works a bit differently: the headend terminal periodically sends a data packet to each client device, telling it exactly when and for how long the OLT is ready to receive its data. Since the transmission duration can change dynamically, there’s no need to break packets into fragments. Of course, this doesn't mean you can blast a massive file—like your favorite movie—all in one go :) No, we're talking about standard Ethernet packet sizes here. Though, during its assigned time slot, an ONT might manage to burst through several packets. Either way, each packet is sent in its entirety. From a purely Ethernet traffic standpoint, GEPON looks pretty attractive, especially since data volumes keep skyrocketing with the rise of internet services and ever-growing demands for high-quality content.

This article is a translation of the original Russian-language post.My journey of learning GPON