GPON, or gigabit-capable PON, uses an IP-based protocol and either ATM or GEM (GPON encapsulation method) encoding. Data rates of up to 2.5 Gb/s are specified and it is very flexible in what types of traffic it carries. GPON enables “triple play” (voice-data-video) and is the basis of most planned FTTP applications in the near future. In the diagram above, one merely drops the AM Video at the CO and carries digital video over the downstream digital link.
EPON or Ethernet PON is based on the IEEE standard for Ethernet in the First Mile. It uses packet-based transmission at 1 Gb/s with 10 Gb/s under discussion. EPON is widely deployed in Asia. The system architecture is the same as GPON but data protocols are differenet.