Summary of Networked Systems Breakout Group

Transcription

1 Summary of Networked Systems Breakout Group Boon Thau Loo NSF ExCAPE PI Meeting 10/11 June 2013

2 Outline Summary (activities over past year) Research highlights Plans for next year

3 Year 1 in Retrospect Original proposal focus: apply appysynthesis s techniques in (1) Internet routing and (2) wireless network protocols Scope of work has expanded over the past year: From synthesizing protocol implementations to synthesizing i policies i and configurations Exciting new applications in Cloud computing and Software defined Networking Deal with management complexity in cloud and highly volatile networked environments

4 Main Participants Faculty: Rajeev Alur (Penn), Ras Bodik (UC Berkeley), Boon Thau Loo (Penn), George Pappas (Penn), Ufuk Topcu (Penn), Madhu Parthasarathy (UIUC) Postdoc: Alexander Gurney (Penn) Students: Behnaz Arzani (Penn), Shaon Barman (UC Berkeley), Sarah Chasins (UC Berkeley), Chen Chen (Penn), Anduo Wang (Penn > UIUC), Shambwaditya Saha (UIUC), Yifei Yuan (Penn), M d f i ti / ll b ti W kl ll Mode of communication/collaboration: Weekly small group meetings, larger group sync ups, monthly webinar, Skype (Penn/India), qualifying exams (Yifei Yuan, Alur/Madhu/Loo), papers, demos.

5 Ongoing Projects (presented yesterday) Internet routing: Routing constraints and traffic disruptions (Gurney, Arzani, Guerin, Loo) FormallySecure Internet routing (Chen, Jia, Loo) Cloud back end: Software defined network configuration synthesis (Wang, Topcu, Loo, Scedrov) Automated bandwidth allocation in data centers (Yuan, Wang, Alur, Loo) Static Scheduling in Clouds (Zufferey, and IST Austria group) Cloud front end: Web scripting for end users (Barman, Chasins, Gulwani, Bodik)

6 Outline Summary (activities over past year) Research highlights Plans for next year

7 #1: Routing Constraints and Traffic Disruptions Participants: Alex Gurney, Behnaz Arzani, Roch Guerin, Boon T. Loo Last year: we presented the Formally Safe Routing (FSR) toolkit > automatically synthesize Internet routing policies that lead to convergence (i.e. safe) This year: two additional dimensions Traffic engineering, Incremental network repair SIGCOMM 12 demonstration and CoNEXT 13 submission

8 Routing Policy Routing policy oftenends ends up being characterized in terms of preferences over paths path p should be better than path q I don t care to choose between p and q Universal llanguage for supporting various business cases, operational concerns, and so on. Example abstraction: routing algebra (in original proposal), declarative networking programs

9 Traffic Engineering We have a network, represented as a (directed, weighted) graph. Routing will establish all pairs shortest paths over this graph. We have a demand matrix of traffic volumes for each source and destination. The shortest paths flow yields link loads (a traffic matrix). Our job: choose weights to minimize load.

10 Challenges and Initial Approaches Routing protocol must converge Minimize congestion network wide These goals are potentially conflicting: Somechoices of linkweights (minimizingcongestion) lead to convergence failure. How can we ensure convergence, while ensuring we get as close as possible to an optimalte solution? Interactive repair: if convergence invariant fails (due to operator error or router failure), how to find a shortest sequence of repairs to minimizetraffic impact? Isshortest shortest sequence of repairs always better? Techniques we explore: Max SMT formulation (Yices), embed path preferences inside existing TE optimization algorithms Evaluated on real network topologies on Emulab

11 #2: Synthesizing Provably Secure Routing Protocols Participants: Chen Chen, Limin Jia, Boon Thau Loo Border Gateway Protocol (BGP) is prone to attacks Prefix hijacking; forged update message Secure alternatives: Secure BGP; so BGP; SCION, ICING,. Lack of formal proof about proposed security guarantees A unified framework for verification and implementation of Internet routing protocol. Use declarative networking for synthesizing secure routing implementations Automated proofs by Coq WRiPE 12 workshop paper, NSDI 13 demo

12 Framework Secure Network Datalog Security Property specification Executable code generator Verification condition generator Distributed implementation ti Proof obligations Wide area deployment Theorem prover 12

13 #3: A Synthesis Approach Towards Automated Management of SDNs Participants: atcpa ts: Anduo Wang, g,uu UfukTopcu, Boon Thau Loo, Andre Scedrov Software defined networking: Centralized controller (programmable in software) Switches can be dynamically programmed: Flow table entries <pattern, action> Used in network virtualization in data centers Traffic isolation dynamic load balancing Traffic isolation, dynamic load balancing OpenFlow standards. Gaining significant traction in industry

14 Challenges and Initial Approaches Given SDN configuration 1, migrate to configuration 2: Determine sequence of routers to update Need to avoid routing loops, and preserve correctness invariants (e.g. traffic isolation, deny certain classes of traffic) Solve as a reachability problem in model checker nusmv Output: an ordering of rule updates Given existing SDN configuration 1, update configurations in response to network state changes Solve as two player temporal logic game Control logic= routing path rule (environment player)+ access control rule (system player) Find a winning strategy for access control rules against all path changes Winning strategy: invariant preserving Dealing with state explosion: Abstraction based on grouping by nodes or flows

15 #4: Automatic Bandwidth Allocation in Data Center s Network Data Centers X 1 X 2 X 3 1G 600M 500M 450M S 1 S 2 S 3 S 4 Boon Thau Loo Yifei Yuan, Anduo Wang, Rajeev Alur,

16 Automatic Bandwidth Allocation in Data Centers Data Center s Network Virtual Network X 1 V 1 400M 400M X 2 X 3 V2 V3 1G 600M 500M 450M S 1 S 2 S 3 S 4

17 Automatic Bandwidth Allocation in Data Centers Data Center s Network Virtual Network X 1 V 1 10G 10G 400M 400M X 2 X 3 V2 V3 1G 600M 500M 450M S 1 S 2 S 3 S 4

18 Automatic Bandwidth Allocation in Data Centers Data Center s Network Virtual Network X 1 V 1 400M 400M X 2 X 3 V2 V3 1G 600M 500M 450M v 1 v 3 v 2 S 1 S 2 S 3 S 4

19 Automatic Bandwidth Allocation in Data Centers Data Center s Network Virtual Network X 1 V 1 400M 400M X 2 X 3 V2 V3 1G 600M 500M 450M v 1 v 3 v 2 S 1 S 2 S 3 S 4

20 Challenges and Initial Approaches NP complete problem Existing heuristics are inefficient but may not find a solution (even if it exists) Our approach: SAT/SMT solving Abstraction and refinement for scalability Exploit hierarchical structure of data centers (Tree, Fat tree) FMCAD 13 submission

21 Other Talks Yesterday #5: Web scripting for end users Shaon Barman, Sarah Chasins, Ras Bodik, Sumit Gulwani Record and replay for web browsers Input: user demonstration of web application Output: script to reproduce the interaction Accessible to end users #6: Static scheduling hdli in the cloud Damien Zufferey et.al. Given a set of jobs, determine a scheduling order that meets optimization goal (total utilization, % deadlines met Challenges: scaling the scheduler, price/performance tradeoffs

22 Outline Summary (activities over past year) Research highlights Plans for next year

23 Plans for next 12 months Continue our current research directions Many projects in early stages Many papers and tool development in the pipeline Evolve into Ph.D. dissertation topics. Co advising would be a plus. Cross layer synthesis (routing, data center networking, cloud scheduling, hdli web scripting) i We welcome your participation and input! We have a lot of networked management problems to work on! Apply computation engines developed by other PIs Opportunities to collaboratewithindustry industry