1. A Novel Multiple Access Scheme for Ethernet Passive Optical Network Professor : Ho-Ting Wu Speaker ： Rui-Yi Jian 2004 – 08 – 11

2. Outline  Introduction  Operation Steps  Conclusion 2004 – 08 – 11

3. Outline  Introduction  Operation Steps  Conclusion 2004 – 08 – 11

4. Introduction  Propose a novel multiple access scheme to efficiently share the upstream channel in an EPON 2004 – 08 – 11

5. Propose  The multiple access scheme contains three parts that operate autonomously but are closely related to each other Parameter-based CAC Mechanism EDA BGP Scheme 2004 – 08 – 11

6. Terminology  OLT Optical Line Terminal  ONU Optical Network Unit  SLA Service Level Agreement  RTT Round-Trip Time  BG Bandwidth Guaranteed 2004 – 08 – 11

7. Generally three class of traffic  Expedited Forwarding (EF) Voice or Video  Assured Forwarding (AF)  Best Effort (BE) Email 2004 – 08 – 11

8. Outline  Introduction  Operation Steps  Conclusion 2004 – 08 – 11

9. Operation Steps  Parameter-based CAC Mechanism  EDA  BGP Scheme Bandwidth Guaranteed Polling 2004 – 08 – 11

10. Parameter-based CAC Mechanism  Call Admission Control  Admits customers in consideration of SLA, through which ONUs can be divided into two disjoint groups served by the OLT differently BG ONUs Non-BG ONUs 2004 – 08 – 11

11. CAC - Parameter  C specifies the minimum peak bandwidth an ONU requests D indicates the maximum waiting delay an ONU can tolerate  E(Di) the worst case average delay E(Di) for each ONU that the OLT pre-calculate 2004 – 08 – 11

12. CAC Mechanism -Initialization Ci*, the OLT re- calculate Check the utilization of network

13. EDA  Evenly Distributed Algorithm  Determines the polling sequence of ONUs for the scheduling scheme 2004 – 08 – 11

14. EDA – Step1  Process the BG ONUs from the one with maximum entries to the one with minimum entries 2004 – 08 – 11

15. EDA – Step2 (1/3)  After determining the first entry Ei[1] and other entries Ei[j] (j=2,3, … Ni) for BG ONUi with Ni entries, fill the Table with this ONU ’ s ID i 2004 – 08 – 11

16. EDA – Step2 (2/3)  Let entry i to be the first entry of ONU i Ei[1] = i  If the entry i is occupied by other ONU Ei[1] = i ± n, n = 1,2,3, … 2004 – 08 – 11 ONU2 ONU6

17. EDA – Step2 (3/3)  Other entries Ei[j] (j=2,3, … Ni), and N is the total entry number of the Entry Table  Ei[j]=mod(Ei[l]+ int(j-1)*N/Ni, N )  Ei[j]=mod((Ei[l]+ int(j-1)*N/Ni) ± n, N ) 2004 – 08 – 11 ONU3 j = 3 Ni = 4 N = 8

18. EDA – Step3  All entries that are not occupied by BG ONUs will be blank in the Entry Table, then assigned to non-BG ONUs dynamically 2004 – 08 – 11

19. EDA – Step4  The List for non-BG ONUs is sequenced in ascending order based on non-BG ONUs ’ IDs  The total number of the elements in the List is not fixed 2004 – 08 – 11

20. EDA – Benefit  It will benefit to the BG ONUs with high traffic since the packets in the buffer can be allowed to transmit after the same intervals  Thus there will be no burst, caused by the scheduling, introduced to the data transmission 2004 – 08 – 11

21. BGP Scheme  Bandwidth Guarantee Polling  The proposed scheme is able to guarantee bandwidth for high- demand users, and provide a best-effort service to low-demand users 2004 – 08 – 11

22. BGP - Steps  The Entry Table & List will determine the scheduling order of ONUs  The OLT sending a control message locate which ONU occupies this entry grants a transmission window to the ONU  Duration of the transmission window The ONU starts to transmit data frames reports its buffer occupancy status 2004 – 08 – 11

23. BGP - Benefit  Entries in the Table that are not occupied by BG ONUs or the superfluous transmission window in one entry that is occupied yet unconsumed by an ONU can be assigned to non-BG ONUs dynamically 2004 – 08 – 11

24. BGP - Problem  How to defined a threshold to determine whether to use the superfluous transmission window or give it up 2004 – 08 – 11

25. Outline  Introduction  Operation Steps  Conclusion 2004 – 08 – 11

26. Conclusion  This scheme can guarantee bandwidth for high-demand customers while providing best- effort service to low-demand customers based on the SLA 2004 – 08 – 11