Passive Optical Network

Passive Optical NetworkByRamesh YadavSenior Verification EngineerCerium Systems

AGENDA

Introduction to PONComponents of PONTypes of PONElaboration of typesEPONGPONPacket formatsDifferences between EPON and GPONQueries

Fiber To The PremisesWe can implement point-to-multipoint topology purely in opticsbut we need a fiber (pair) to each end userrequires 2 N optical transceiverscomplex and costly to maintainN end userscoreaccess networkActive Optical Network

Deploy intermediate switches (active) switch located at curb or in basementsaves space at central officeneed 2 N + 2 optical transceivers

corefeeder fiberfiber Passive Optical Network

Implement point-to-multipoint topology purely in opticsavoid costly optic-electronic conversions use passive splitters no power neededonly N+1 optical transceivers (minimum possible) !1:2 passive splitter1:4 passive splitterN end usersfeeder fibercoreaccess networktypically N=32max defined 128PON advantagesShared infrastructure translates to lower cost per customerminimal number of optical transceiversfeeder fiber and transceiver costs divided by N customersgreenfield per-customer cost similar to UTPPassive splitters translate to lower costcan be installed anywhereno power neededessentially unlimited MTBFFiber data-rates can be upgraded as technology improvesinitially 155 Mbpsthen 622 Mbpsnow 1.25 Gbpssoon 2.5 Gbps and higher

TerminologyPON technology has its own terminologyCO Central OfficeOLT Optical Line TerminalONU Optical Network UnitsDS Down stream i.e OLT to ONUUS Up Stream i.e ONU to OLT

downstreamOptical Network UnitsupstreamOptical Distribution NetworkNNITerminal EquipmentUNI`coresplitterOptical Line TerminalOptical Access NetworkMany types of PONs have been defined APONATM PON BPONBroadband PON GPONGigabit PON EPONEthernet PON GEPONGigabit Ethernet PON CPONCDMA PON WPONWDM PONPON Types

PON DefinitionPoint to multipoint optical networksArchitecture build up from two elementsAn Optical Line Terminal (OLT) at Network Provider's premisesMultiple Optical Network Units at users' premisesFiber to the home solution (FTTH) Fiber to the business solution (FTTB)Fiber to the curb solution (FTTC)Transmissions occur between OLT and the ONUsNo active elements in signals' pathEmploy passive combiners, couplers and splitters only.Ethernet PON Data is encapsulated in Ethernet framesIEEE 802.3ah Ethernet in the first mile

Ethernet PON