A Theory of Cloud Bandwidth Pricing for Video-on-Demand Providers

Transcription

1 A Theory of Cloud Bandwidth Pricing for Video-on-Demand Providers Di Niu, Chen Feng, Baochun Li Department of Electrical and Computer Engineering University of Toronto IEEE INFOCOM 2012, Cloud/Grid computing and networks Session Yunhyoung Kim

2 Introduction Problem Setting Analysis Table of Contents Condition that = Social Planner Optimal Pricing Strategy of Tenants Simulation Results Summary and Conclusion

3 Introduction In order to serve VoDs, VoD provider should prepare VoD Provider Contract with Cloud Provider Buy & Maintain Hardwares Contract with ISP Cloud Provider VoD is sensitive to bandwidth change Bandwidth Reservation 1) How much BW should VoD provider reserve? 2) Cloud provider uses pay-as-you-go model BW not guarenteed A broker can solve this situation Provide Network Service Environment (Network BW, Servers, etc.) Cloud Providers

4 Introduction What broker is expected to do : - Bandwidth Guarantee - Saving network cost by Multiplexing - Workload distribution Cloud Providers 100Mbps Mixing / BW 100Mbps 200Mbps Total / Mbps GB 300Mbps / 1Gbps Workload Consolidation Cloud Providers Why this works : 1) VoD Demand Varies 2) Correlation between : are distinguished according to genre, preferences of videos they deal with

5 Introduction assumptions However, broker want to improve its utility, Profit Small payment BW not guaranteed Do not consolidate workload if it is not profitable VoD Provider Cloud Provider VoD providers would not use broker if the price is high Cloud Providers Cost = $1 per 1M Cost > $1 per 1M A deal between VoD provider and Submit pricing strategy Service fraction

6 Introduction Contribution of this paper Analysis on the pricing condition that they produce the same result Wants to maximize profit Social Planner Wants to minimize aggregate workload Analysis on optimal pricing strategy of each VoD providers optimal pricing strategy belongs to the pricing condition Profit-maximizing broker minimizes the aggregate workload, thereby minimizing the cost of

7 Problem Setting = Tenants BW demand of tenant Service workload fraction of tenant Service workload fraction of tenant, served by cloud provider Bandwidth Capacity of cloud provider Bandwidth of cloud provider, booked by broker Workload of cloud provider 1 VoD Provider Demand : (with and ) Risk Factor : In order to satisfy with prob. 1, broker should reserve BW from CP Decides ( ) Risk Factor : In order to satisfy with prob. 1, broker should reserve BW from CP Cloud Provider Bandwidth Capacity : Assumption : is sufficiently large to accommodate all the services.

8 1st Part : Pricing Condition that = Social Planner Let s see the pricing condition making = Social Planner Analysis on the pricing condition that they produce the same result Wants to maximize profit Social Planner Wants to minimize aggregate workload

9 Pricing Condition that = Social Planner Profit = Sum of Prices (from tenants) Payment to CSP Decides ( ) Social Planner s Profit Maximization : charges of tenant regarding its demand is pricing strategy : payment to the cloud service provider ($1 is a fee for a unit BW, for a period) as a social planner Objective = minimize Payment to CSP Workload consolidation problem Under what ( ) the broker act as a social planner?

10 Pricing Condition that = Social Planner Find ( ) which satisfies : Workload Consolidation Profit Maximization Warm up for a second.. : market demand with standard deviation ( ) : covariance between and ( ) Correlation coefficient between and : Demand : (with and ) Gaussian Random Variable Workload of Server s : Gaussian Random Variable

11 Pricing Condition that = Social Planner Workload Consolidation Optimal Solution : where if 1 2 Cloud Providers = = = = = = = = = = = = BW saving : = = = = = + = 1 Tenant 1 get fully served

12 Pricing Condition that = Social Planner So.. What is ( ) that makes a broker a social planner? : Profit Maximization Workload Consolidation Solution of Profit Maximization = Solution of Workload Consolidation Theorem. These two problem have a same optimal solution if and only if Lemma. Concave function ( ) on 0,1 with 0 = 0 satisfies if 1 for 0,1.

13 Pricing Condition that = Social Planner Corollary. With a pricing policy ( ) that makes broker = social planner, each ( ) satisfies Contract with = Contract with Cloud Provider : Expected bandwidth tenant i require With good pricing, all the tenents get fully served!! s profit broker s profit is the same as bandwidth saving Savings from bandwidth multiplexing rewarded to tenants

14 2nd Part : Optimal Pricing Strategy of Tenants So far, we have seen the pricing condition of Wants to maximize profit Analysis on the pricing condition that they produce the same result Social Planner Wants to minimize aggregate workload Next, we will see VoD provider s optimal pricing strategy.. Analysis on optimal pricing strategy of each VoD providers optimal pricing strategy belongs to the pricing condition

15 Optimal Pricing Strategy of Tenants What is pricing strategy Tenants want to 1) get fully served, and 2) reduce price Submit pricing strategy Service fraction ( ) of each selfish tenant? Theorem. If broker maximizes its profit, then an optimal strategy of each tenant will converge to a unique NE Lemma. If, then regardless of Proof Sketch of NE i) ii) : Theorem. s problems have the same optimal solution iff.

16 Optimal Pricing Strategy of Tenants Tenant s optimal pricing strategy belongs to s good pricing strategy All the tenants should pay No profit for broker. Is this reasonable? : Agent fee, Membership fee, etc. - Correlation between VoD Provider and All of them : A VoD Provider can be distinguished according to genre, preferences of videos they deal with

17 Trace-Driven Simulations Bandwidth Saving Payment Discounts When is negative

18 Summary and Conclusion Analysis on the pricing condition that they produce the same result Wants to maximize profit Social Planner Wants to minimize aggregate workload Analysis on optimal pricing strategy of each VoD providers optimal pricing strategy belongs to the pricing condition Profit-maximizing broker minimizes the aggregate workload, thereby minimizing the cost of Assumed that VoD providers can negotiate with BW they need. It would be different in a real world (brokers name their prices, etc.)