Fair Sharing Using Service-Level Agreements (SLAs) for Open Access in EPON

1. Fair Sharing Using Service-Level Agreements (SLAs) for Open Access in EPON Amitabha Banerjee, Glen Kramer, Biswanath Mukherjee {abanerjee, gkramer, bmukherjee}@ucdavis.edu

2. Voice + Video + Internet SP A Voice + Video SP B Video + Conferencing SP C Video + Playstation SP D SP E Voice + Video + Playstation Open Access Network - Illustration End users: FTTx ONU OLT ONU Neutral EPON access network SP = Service Provider ICC 2005, Seoul, South Korea

3. The Shared Access Channel • Define an active connection between an SP and a user as a flow. • Possible approaches to fairness: • Fair sharing between flows. • Fair sharing between users. • Fair sharing between SPs. • Fair sharing between both users and SPs simultaneously (By having Dual SLAs). ICC 2005, Seoul, South Korea

4. Allocated (units) Allocated (units) 10 10 10 40 10 10 10 10 20 10 10 20 10 Fair Sharing Between Flows Queue size (units) Equal share to each independent flow e.g. Deficit Round Robin (DRR) 15 Qa1 U1 SPa 15 Qa2 U2 Qa3 15 C = 60 units U3 Qa4 15 U4 15 Qb4 SPb U5 15 Qb5 Fair to neither SPs nor Users ICC 2005, Seoul, South Korea

5. Fair Sharing Between Users Queue size (units) Allocated (units) Equal share to each User Allocated (units) 12 15 Qa1 U1 12 SPa 12 15 Qa2 42 U2 12 Qa3 12 15 12 C = 60 units U3 Qa4 6 15 12 U4 15 6 Qb4 SPb U5 12 18 12 15 Qb5 Not fair to SPs ICC 2005, Seoul, South Korea

6. Fair Sharing Between SPs Queue size (units) Allocated (units) Equal share to each SP Allocated (units) 7.5 15 Qa1 U1 7.5 SPa 7.5 15 Qa2 30 U2 7.5 Qa3 7.5 15 7.5 C = 60 units U3 Qa4 7.5 15 22.5 U4 15 15 Qb4 SPb 30 U5 15 15 15 Qb5 Not fair to Users ICC 2005, Seoul, South Korea

7. Allocated (units) Allocated (units) 10 10 10 35 10 10 10 5 15 10 15 25 15 Fair Sharing Using Dual SLAs Queue size (units) Use Dual SLAs User SLA = 10 units (primary) SP SLA = 25 units (secondary) 15 Qa1 U1 SPa 15 Qa2 U2 Qa3 15 C = 60 units U3 Qa4 15 U4 15 Qb4 SPb U5 15 Qb5 Objective: To be fair to both SPs and Users ICC 2005, Seoul, South Korea

8. Time cycle of max duration T Packets arrive Packets transmitted gc1 ga2 gb1 ga1 gb2 Time-slot assigned to each flow Next invocation of Scheduling Algorithm. Scheduling Algorithm invoked Scheduling Time-slots for Fairness ICC 2005, Seoul, South Korea

9. Global Parameters R: EPON bit rate M: # of SPs N: # of Users UjMIN: User SLA (pri) WiMIN: SP SLA (sec) Time cycle parameters C = R * T ujMIN= UjMIN * T wiMIN= WiMIN* T T = Maximum duration of time cycle. Scheduling Parameters ICC 2005, Seoul, South Korea

10. Scheduling • Given • Time t at which scheduler is invoked • qi,j,t: Queue size for queue from SPito User j • Determine • ∆: Scheduling time cycle duration • gi,j,t,t+∆: Bandwidth allocated for SP i to User j • Constraints • Bandwidth allocation constraint, gi,j,t,t+∆ ≤ qi,j,t • Capacity constraint, Σi Σj gi,j,t,t+ ∆ ≤ C • Maximum scheduling time cycle constraint, Tadv ≤ ∆ ≤ T ICC 2005, Seoul, South Korea

11. Max – Min Fair Bandwidth • Bandwidth allocation to poorest entity Q4 Q3 Q2 Q1 ICC 2005, Seoul, South Korea

12. Start Is demand < capacity of maximum timeslot ? Yes No Case I Allocate grants equal to demand Case II Step 1: Identify mandatory grants. Step 2: Allocate Grants to meet Secondary SLA Step 3: Allocate grants to meet Primary SLA. If sufficient capacity is not available, then recover grants assigned in Step 2 to meet deficit. Step 4: Grant remaining timeslot fairly amongst users. Algorithm • Is • demand < capacity of • maximum timeslot ? • -------------------------------------- • Is • ΣiΣj gi,j,t,t+ ∆ ≤ C ? Step 3: Allocate grants to meet Primary SLA. If sufficient capacity is not available, then recover grants assigned in Step 2 to meet deficit. ------------------------------------------------------------------------------------- availBW = C – ΣiΣj gi,j,t,+∆ demandUserj = MIN [ ujMIN, Σiqi,j,t ] preAssignedUserj = Σigi,j,t,t+ ∆ Assign Max-Min fair BW amongst users For all users for which demandUseri not met: Invoke Algorithm RecoverBW • Case I • Allocate grants • equal to demand • --------------------------------- • gi,j,t,t+∆ = qi,j,t • ∆ = Max [Tadv, Σi Σj qi,j,t/ R] • Case II • Step 1: • Identify mandatory grants. • ------------------------------------- • User j: Σi qi,j,t < ujMIN • User subscribed to single SP Step 2: Allocate Grants to meet Secondary SLA ------------------------------------------------------ availBW = C – ΣiΣj gi,j,t,+∆ demandSPi = MIN [ wiMIN, Σjqi,j,t ] preAssignedSPi = Σj gi,j,t,t+ ∆ Assign Max-Min fair BW to SPs Similarly for each User within SP Step 4: Grant remaining timeslot fairly amongst users. --------------------------------------------------------------- Assign Max – Min fair BW to users Similarly for SPs for each User ICC 2005, Seoul, South Korea

13. gi’,j,t,t+∆ deficit Algorithm Recover Bandwidth Recover BW from different SPs Recover BW from same SP gi’,j’,t, t+∆ UMIN UMIN Ui Ui’ SPj’ Ui Ui’ No change in SP allocations SP SLA may be violated ICC 2005, Seoul, South Korea

14. Simulation Model ONU SP SLA is 150 Mbps per SP User SLA is 50 Mbps per User OLT 1 Gbps EPON 16 users 6 SPs Traffic is generated to be self-similar with Hurst Parameter of 0.8 ONU ICC 2005, Seoul, South Korea

15. Traffic Matrix ICC 2005, Seoul, South Korea

16. Results (SPs) – DRR ICC 2005, Seoul, South Korea

17. Results (SPs) – Dual SLA ICC 2005, Seoul, South Korea

18. Results (Users ) - DRR ICC 2005, Seoul, South Korea

19. Results (Users) – Dual SLA ICC 2005, Seoul, South Korea

20. Conclusion • Open access requires sharing of bandwidth between both users and SPs. • The above may be achieved by using the Dual SLA Scheduling Algorithm. • Dual SLA Scheduling Algorithm has good fairness properties. ICC 2005, Seoul, South Korea

21. Questions ? • For further details please contact • Amitabha Banerjee at abanerjee@ucdavis.edu • Glen Kramer at gkramer@ucdavis.edu • Biswanath Mukherjee at mukherje@cs.ucdavis.edu ICC 2005, Seoul, South Korea