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Passive Optical Broadband Communications in Local Access Network

Passive Optical Broadband Communications in Local Access Network. Kae-hsiang Kwong 21 January 2004 kkhsiang@eee.strath.ac.uk. What is an Access Network?. Backbone Network Internet PSTN CATV. Access Networks provide necessary interfaces to end-users accessing telecommunication services.

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Passive Optical Broadband Communications in Local Access Network

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  1. Passive Optical Broadband Communications in Local Access Network Kae-hsiang Kwong 21 January 2004 kkhsiang@eee.strath.ac.uk

  2. What is an Access Network? Backbone Network Internet PSTN CATV Access Networks provide necessary interfaces to end-users accessing telecommunication services. Access Network Feeder + Distribution Access unit

  3. Evolution of Access Networks Telephony Cable TV Internet Telephony + Internet Cable TV + Internet Telephony + Cable TV + Internet

  4. Passive Optical Access Networks PON: network architecture constructed solely using passive optical devices; no signal regeneration in the transmission path. Backbone network PSTN CATV Internet ONU Combiner OLT ONU users ONU Backbone network Copper network Optical fibre network

  5. Medium Access Control • Interleaved Polling with Adaptive Cycle Time (IPACT) • Provides Dynamic bandwidth allocation. • OLT assigns each ONU for transmission based on the information exchanged between OLT and ONUs. • Buffer status and traffic load of ONU sent to OLT. • OLT utilises incoming information to schedule ONU transmissions. • OLT issues Grants to inform individual ONUs start time and duration of transmission.

  6. ONU 1 Combiner OLT ONU 2 ONU 3 ONU 2 ONU 1 users ONU x Medium Access Control G G G • Grant is broadcast to every ONU. • Information is carried to OLT at the end of each ONU transmission.

  7. WDM IPACT + DiffServ DS Network Packets from users Class 1 Classifier Class 2 scheduler Class 3 ONU OLT • ONU: • Incoming packets are classified and marked. • Traffic flows are grouped into traffic classes according to the similarity of QoS requirements. • Different level of reservation treatments applied to each traffic class. • OLT: • Bandwidth are allocated to ONUs according to the buffer status and traffic load. • Associates traffic classes to bandwidth allocation schemes.

  8. Conclusion • WDM PON systems • 1. WDM-IPACT with fixed transceivers. • 2. WDM-IPACT with tuneable transmitters, fixed receivers. • Highly cost efficient solution in upgrading access network. • Single network architecture, supporting Telephony, CATV broadcast, Internet, etc. • DS domain extended to local access networks. • Achieves end-to-end QoS provisioning. • Eliminates the need for per-flow resource reservation.

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