GPON Introduction Basic

by pk-admin Gpon

Gigabit Passive Optical Network

A GPON system consists of three Parts ;OLTs in Site, ONU/ONTs in clients/Customer home and ODNs(Passive network). A PON is a point-to-multipoint optical network. It uses  WDM (wavelength division multiplexing) technology and single optical fiber for transmitting and receiving.

1.OLT: Optical Line Terminal

  • The OLT provides optical interfaces to passive optical networks, processes the service traffic from multiple accessing points.
  • Transmits data to the ONU/ONT through multicast.
  • Implements service adaptation.
  • Initiates and controls the distance measuring process, and records the distance information.
  • Assigns T-CONT (Transmission Container) upstream bandwidths.
  • Implements L2/L3 Ethernet functions.
  • Manages ONU through OMCI protocols.

2.ONU/ONT: Optical Network Unit

The ONU/ONT is a user-side CPE device, which provides multiple user interfaces(Lan Cable, WIFI). Functions as follows:

  • Selectively receives broadcast data sent by the OLT.
  • Implements service adaptation, and multiplexing/demultiplexing.
  • Responses to the distance measurement command sent by the OLT and makes some adjustments.
  • Caches user data and transmits the data in the upstream in the T-CONT assigned by the OLT.

3.ODN: Optical Distribution Network

An ODN consists of one or more Passive devices .No electric power required .For Example ODF, Splitter, ODB etc.

The Optical Splitter merely divides the optical power into N separate paths to the users. It split one fiber into 32,64,128 .