End-to-end QoS negotiation in network federations

Transcription

1 End-to-end QoS negotiation in network federations H. Pouyllau, R. Douville Avril, 2010

2 Outline Motivation for Network federations The problem of end-to-end SLA composition Scenario of composition and negotiation Definitions and problem formulation Game model Conclusion 2 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

3 Big picture of the Internet I want to do Cloud computing! Operators had their time, now comes the OTTs age I want more bandwidth for free! The Future Internet belongs to robots We need to upgrade our equipments to sustain your demands, give us compensation You may see Internet as a black box The reality is much more complex Pay me I m famous! And I, remote surgery! Paying for bandwidth, are you kidding me? 3 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

4 Diagnosis To support future high performance applications, today s Internet is facing major issues : Need for End-to-end QoS guarantees (bandwidth, latency, availability, reliability, security, etc.) not possible to extend the current protocol (scalability, confidentiality concerns) Risk of divergence (2 different Internet networks) Reconsider economic agreements Following the historic Tiers hierarchy, new interconnections might be needed Operators will not guarantee anything without compensations Revenue may be cannibalized by OTTs (e.g. Disney) Internet networks must undergo significant transformations: New business models to provide operators incentives to upgrade their infrastructures and deploy new management architectures New architectures, protocols, algorithms that will realize these new business models and enable the on-demand/scheduled establishment of end-to-end QoS guaranteed connection 4 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

5 Different revenue models and associated organization N 1 - Coalition SLSs + cost information This model might not be accepted by regulation Authorities + confidentiality on costs N 2 - Open Market SLSs + bids Several properties to be respected (efficiency, budget balance, etc;). Need to be incentive enough for operators so that they cooperate N 3 Federation/Alliances SLSs + Prices Inline with operators expectations + incentives to cooperate + no cost disclosure 5 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

6 Alliance Business model «When transaction costs are high, the alliance governance structure is the best suited to manage transactions with an intermediate degree of asset specificity [ ] Williamson 1991 Centralized alliance of operators, a Third party handles critical processes ensuring confidentiality on sensitive data Third party Distributed alliance of operators, processes respect confidentiality requirements by construction IC Agent IC Agent IC Agent IC Agent 6 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

7 Outline Motivation for Network federations The problem of end-to-end SLA composition Scenario of composition and negotiation Definitions and problem formulation Game model Conclusion 7 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

8 End-to-end SLA composition problem Q 0 C 1 C 2 Carrier Carrier 0 0 C K C 1 C 2 Carrier Carrier 1 1 C 1 C K Carrier C Carrier C 2 C K Carrier Carrier 3C 2 3 C K 8 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

9 Focus on Step 1 : A possible scenario A possible scenario: 1. A customer requests a service with a (normalized) level of QoS 2. The third party (i.e. a centralized entity receiving customer demands and having access to SLS repositories) treats the request 1. Find a chain of SLSs that satisfies the required QoS demand profile 2. Asks each participant carrier about the bandwidth availability for its corresponding SLS 3. The third party makes an offer to the customer 4. The customer accepts or refuses 5. If the customer accepts, SLSs are committed as SLAs 9 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

10 0 1 Definitions General definition: a SLA (Service Level Agreement) is a committed SLS (Service Level Specification). A SLS represents network resource capabilities in an abstract manner (end-points, thresholds over QoS parameters, etc.) thus avoiding Topology and Capacity publishing Formal definition: In a network federation, aach carrier i publishes J i SLSs. A SLS s ij, j=1,, J i is a tuple (D ij, L ij, B ij, P ij, (in ij, eg ij )) where D ij, L ij, B ij are guarantees on delay, packet-loss and bandwidth (other parameters such as availability could be represented); P ij is a price; (in ij, eg ij ) is a pair of ingress and egress nodes, between which parameters are guaranteed Customer demands are formulated similarly : (D r, L r, B r, P r,s, t)) where QoS parameters corresponds to the choice of a normalized profile of demand k=1,, K, P r is not disclosed, s and t are the source and target nodes. 10 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

11 Problem formulation Optimization criteria could be added Published data Solved when providers check the SLS availability 11 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

12 Outline Motivation for Network federations The problem of end-to-end SLA composition Scenario of composition and negotiation Definitions and problem formulation Game model Conclusion 12 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

13 2 games 1st game : providers compete on prices Incomplete information, providers can only observe the frequency of SLS demands 2nd game : third party and customer Focus on the 2nd game (the 1st game is played before) 2 players N players when repeated Extensive game with incomplete information Utilities: Third party: whole provider utilities, depends on the customer/provider acceptance, objective is to maximize a long-term (discounted) revenue Customer: depends on price, QoS proposed, etc. -> unknown but for a same QoS profile of demand a customer prefers to pay less. 13 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

14 Game model : Third party and Customer Players strategies Customer : chooses a demand profile k and has a limit of price, p bk he is ready to pay; a customer accepts or refuses a proposition. Third party : proposes a SLS chains C k among the SLS chains satisfying profile k and C k is associated to a price p(c k ) we assume this price is the sum of the prices of the SLSs composing chain C k Histories Any history has the form ((k, p bk ), C k, v) where v={ y, or n } Preferences/Utilities no accurate model of customer utility Assumption 1 : for a same QoS, a customer will prefer to pay less Assumption 2 : if all the SLS chain prices are superior to the customer price bound, he will refuse any proposition 14 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

15 Game model : Third party and Customer Nash equilibrium A dominant strategy for the 3rd party is to choose the chain having the lowest price NE when the game is repeated A subgame equilibrium is attainable, after an infinite number of steps: the third party chooses the chains by decreasing values of prices until the customer accepts, similarly the customer can refuse all proposition until he discover the least cost one Problem : the third party reveals all information, still the dominant strategy is to choose the chain having the lowest price. But does it meet the federation objective? 15 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

16 Conclusion Network federation : A new organizational model for ISPs No cost disclosure, price competition, respect of confidentiality Enables incentives for networks to provide QoS Next steps Learning mechanisms to study customer utilities Study of the game between providers Interactions between game 1 and 2 Open issues Comparison of incentives provided by different organizational models Regulation issues 16 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009

17 Questions Contact: 17 Solving the end-to-end SLA composition problem October 2009 All Rights Reserved Alcatel-Lucent 2009