Most GPON optical modules come in SFP form factor, which allows hot-pluggability and compatibility with various OLT or ONU devices. Central to the GPON system is the Optical Line Terminal (OLT), the core device responsible for aggregating data streams, managing Optical Network Terminal/Unit (ONT/ONU) devices, and performing application distribution and network management. When you stream a 4K video, join a remote meeting, or play an online game on a gigabit fiber connection, an OLT. This document describes the Gigabit Passive Optical Network (GPON) technology and how it functions. There are no specific requirements for this document. This document is not restricted to specific software and hardware versions.