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

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

3. Background Review 3

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

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) 5

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

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

8. Operation principle 8

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 9

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

11. Online scheduling Stop and poll polling policy 11

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

13. IPACT example 13

14. IPACT example 14

15. IPACT example 15

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 16

17. Transmission window 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 17

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

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 19

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

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

22. Simulation work 22

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 23

24. Simulation parameters ONU number16 Uplink transmission rate1Gb/s Simulation time30s RTT time /transmission distanceUniform(100~200)us /10~20km Offered network load (ONU’s maximum input traffic rate) 0.08~1.6(Gbps) (100Mb/s) Maximum cycle time2ms Guard time5us Packet sizeP0 : fix at 70 bytes P1, P2 : Uniform(64~1518) bytes Traffic type_1 P0 fix at 4.48Mbit/s ， P1,P2 : Remain loading*50% Packet generate methodP0 : Constant bit rate P1, P2 : Poisson distribution Measurement metricsDelay Maximum transmission window size15000 bytes 24

25. Simulation result 25

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36. Remaining work Define a DBA which base on offline scheduling that can well reduce idle time on EPON system. 36

37. Reference 37 [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,”IEEE Communications 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.

38. Q&A 38