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The Design of Offline Scheduling Mechanisms on EPON

The Design of Offline Scheduling Mechanisms on EPON. Professor : Ho-Ting Wu Student : Pei- Hwa Yin. Outline. Back ground review DBA introduction Simulation work so far Remaining work Q&A. Background Review. PON’s origination.

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The Design of Offline Scheduling Mechanisms on EPON

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  1. The Design of Offline Scheduling Mechanisms on EPON Professor : Ho-Ting Wu Student : Pei-Hwa Yin

  2. Outline • Back ground review • DBA introduction • Simulation work so far • Remaining work • Q&A

  3. Background Review

  4. PON’s origination • Bandwidthbottleneck between end users and backbone networks • PON can provide more bandwidth to end users in a cost-effective way

  5. EPON’s advantages • low-cost Ethernet equipment and low cost passive optical components • lower cost for equipment maintenance • larger bandwidth capacity • longer transmission distance(10~20km)

  6. EPON Architecture • point-to-multipoint fiber optical network with no active elements in the transmission path from source to destination

  7. Operation principle • In an EPON system all data are encapsulated in Ethernet packets for transmission

  8. Operation principle

  9. Multi-Point Control Protocol(MPCP) • Being developed by the IEEE 802.3ah task force. • This protocol relies on two Ethernet messages : GATE and REPORT to achieve dynamic bandwidth allocation process • GATE : assign time slot • REPORT : report ONU’s local queues condition

  10. Dynamic Bandwidth Allocation (DBA)Mechanism Online scheduling Offline scheduling

  11. Online scheduling • Stop and poll polling policy

  12. Interleaved Polling with Adaptive Cycle Time(IPACT) • IPACT mechanism concept

  13. IPACT example

  14. IPACT example

  15. IPACT example

  16. Transmission window • OLT use transmission window to notify ONU let ONU knows that how many data it can upload in a cycle. • Max transmission window size • It’s a threshold that use to forbid ONU upload too many data in a cycle

  17. Transmission window • The way to determine the Transmission window size • Limited service If (request>Transmission window size) Transmission window size=Max transmission window size else Transmission window size=request • Gated service Transmission window size=request • Fixed service Transmission window size=Max Transmission window size

  18. Offline scheduling • Once OLT collect Report message from all ONUs, then start to send Gate messages to response ONU.

  19. Offline scheduling • Partial ONU in two groups • High load and light load • Let ONUs which belong the high load group can use excess bandwidth to transmit more data

  20. Offline scheduling • Guarantee bandwidth computation • Excess bandwidth assignment • After DBA Bandwidth assignment

  21. Offline scheduling with early allocation scheme • if (Request<=guarantee bandwidth) Grant bandwidth right away else Grant bandwidth after collect all REPORT messages

  22. Simulation work

  23. Simulation description • Model1(M1) • Offline scheduling mechanism • Model2(M2) • Offline scheduling with early allocation scheme • Intra-ONU bandwidth assign methods[1] • Strict Priority • Priority queuing • (OLT)Central control

  24. Simulation parameters

  25. Simulation result

  26. Remaining work • Define a DBA which base on offline scheduling that can well reduce idle time on EPON system.

  27. Reference [1] C.M. Assi, Yinghua Ye, Sudhir Dixit, and M.A. Ali, “ Dynamic bandwidth allocation for quality-of-service over Ethernet PONs ,”IEEE Journal on Selected Areas in Communications, vol.21, no.9, pp. 1467-1477, November 2003. [2] G. Kramer, B. Mukherjee, and G. Pesavento, “Interleaved Polling with Adaptive Cycle Time (IPACT): A Dynamic Bandwidth Distribution Scheme in an Optical Access Network,”Photonic Network Communications, vol. 4, no. 1 pp. 89-107, January 2002. [3] J. Zheng and H.T. Mouftah, “Media access control for Ethernet passive optical networks: an overview,”IEEECommunications Maganize, vol.43, no2 pp.145-150 , February 2005. [4] G. Kramer, Ethernet Passive Optical Networks, McGraw-Hill Professional,ISBN: 0071445625, Publication date: March 2005.

  28. Q&A

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