Tools for the Analysis and Design of Complex Multi-Scale Networks: Overview

1. MURI Annual ReviewColumbus OH, October 14, 2010 J. Walrand, PI Tools for the Analysis and Design of Complex Multi-Scale Networks:Overview

2. Venkat Anantharam, UCB John Doyle,Caltech Weibo Gong, UMASS Steven Low, Caltech R. Srikant, UIUC Don Towsley, UMASS Jean Walrand, UCB Avideh Zakhor, UCB 14 PhD Students, 7 Postdocs 14 Journal Papers, 22 Conference papers 1. Team

3. 2. Scientific Objectives and Technical Approach

4. 2. Scientific Objectives and Technical Approach High Throughput Low Energy Low Delay Security Reliability

5. 2. Scientific Objectives and Technical Approach High Throughput/ Low Energy Low Delay Optimization-Based Protocols HT & LRD mitigation Statistical Network Measurements Methodology for LRD Security Reliability Noise-Based Schemes Game: Attack/Defense

6. 3. Scientific Issues Local Information - Global Impact Multiple Time Scales: LRD traffic Link Fading MAC Adjustment Routing Congestion Control Uncertainty Security Concerns

7. 4. Scientific Accomplishments High Throughput/ Low Energy Low Delay Mitigate HT through - multiple paths - file partitioning Adaptive CSMA Protocols Optimization-Based Protocols HT & LRD mitigation Optimization-Based Protocols Improved WiFi w. error classification Energy Efficiency Statistical Network Measurements Statistical Network Measurements Frontier Sampling of Large Networks Methodology for LRD Methodology for LRD SDE Models & Stochastic Approximations for LRD Security Reliability Dynamic Shared Secrets Noise-Based Schemes Noise-Based Schemes Graph Vulnerability; Strategies w. Uncertainty Game: Attack/Defense

8. 4. Scientific Accomplishments High Throughput/ Low Energy Low Delay Multipath – Wei Wei Mitigate HT through - multiple paths - file partitioning Mixing & Bounds - Srikant Adaptive CSMA Protocols Optimization-Based Protocols HT & LRD mitigation Optimization-Based Protocols Improved WiFi - Zakhor Improved WiFi w. error classification Energy Efficiency Scheduling & Energy – Lavaei, Low Statistical Network Measurements Statistical Network Measurements Frontier Sampling of Large Networks Sampling of Large Networks - Towsley Methodology for LRD Compression & Stochastic Approx. - Anantharam Methodology for LRD SDE Models & Stochastic Approximations for LRD Security Reliability Noise-Based Schemes Dynamic Shared Secrets - Xiao Dynamic Shared Secrets Noise-Based Schemes Game: Attack/Defense Graph Game; Optimism - Walrand Graph Vulnerability; Strategies w. Uncertainty

9. Adaptive CSMA Protocol CSMA with mean backoff delay decreasing in backpressure [Mathematically: Maximize Entropy + Utility] This distributed protocol achieves the Maximum Throughput [Intuition: Approaches Maximum Weight after Mixing Time] Libin Jiang & Jean Walrand capacity region Delay Polynomial in Number of Links [Intuition: Fast Mixing when load is small] Jiang, Leconte, Ni, Srikant, Walrand low delay region

10. Question: What causes packet drops? Noise, Hidden Node, Exposed Node? Improved WiFi with Error Classification[Zakhor, Krishnan, Haghani] • Method to get answer: Combine local channel activity with AP channel activity • Use that information to adapt link => up to 400% throughput increase • Adaptive carrier sense threshold algorithm => up to 50% throughput increase • Verified performance through comprehensive NS-2 simulations.

11. Example: Entropy density of a long range dependent renewal process also long range dependent with same Hurst exponent. Hence lossless compression does not reduce LRD Compression of LRD Processes[Anantharam, Barlas] • Tradeoff LRD vs. Compression Loss • Characterization of functionals of LRD Markov chains that are also LRD

12. File Fragmentation to Avoid Heavy Tails[Low, Doyle] • Motivation: Can retransmission create heavy-tailed filetransfer times even when file sizes are light-tailed? • Analysis: • In general, YES! • Avoided with reasonable fragmentation policies • Optimal policy uses constant fragment size • Design: • Blind policy that is robust and • asymptotically optimal

13. Alice sends packets to Bob Bob sends feedback listing correctly received packets Alice, Bob generate a key using correctly received packets Dynamic Shared Secrets[Gong, Towsley] Bob Alice Eve Nonzero probability that Bob receives packets Eve did not! Unreliability: Wireless channels unreliable by nature Independence: Wireless channels have independent error behavior as long as not co-located ⇒ Alice, Bob can generate private key

14. Collaboration UIUC - UCB Delays in Adaptive CSMA Protocol Impact of Collisions Collaboration UMASS - CALTECH File Partitioning Algorithms Collaboration UCB – CALTECH Libin Jiang (UCB postdoc) will join Caltech (postdoc) in September Collaboration across projects UMASS – Shroff: Mutlipath protocols and LRD Future collaboration across projects Exploration of delay-based protocols Combination of LQF and Adaptive CSMA 5. Group Synergy

15. Alternative Metrics for Wireless Networks Likelihood of delivery within deadline Maximum reliability deliveryEnergy Dynamic control approach to protocol design Improve transient behavior and performance with mobility Control methodology for LRD Based on new SDE models Refinements of improved WiFi protocols Based on loss differentiation Collaboration on transition Support for implementation of new algorithms and protocols 6. Future Plans

16. 9:20AM — 10:00AM Heavy Tails: Compression and Stochastic Approximations (Venkat Anantharam) 10:00AM — 10:30AM Dynamics, Security, Uncertainty (Jean Walrand) 10:30AM — 10:45AM Coffee Break 10:45AM — 11.25AM Throughput Enhancement in Wireless LANs (Avideh Zakhor) 11:25AM — 12:05PM Multipath Communications and Power Laws (Wei Wei) 12:05PM — 1.00PM Lunch Break 1:00PM — 1:25PM Dynamic Secrets in Wireless Communications (Sheng Xiao) 1:25PM — 1:50PM Sampling large complex networks (Don Towsley) 1:50PM — 2:30PM Mixing Time of Parallel Glauber Dynamics and Queue Length Bounds for CSMA Scheduling (R. Srikant)  3:00PM — 3:20PM Break 3:20PM — 4:00PM Overview of Caltech Projects, Scheduling & Energy Efficiency with Heavy Tail (Steven Low) 4:00PM — 4:40PM Optimal Wireless Protocols and Devices (Javad Lavaei) 4:40PM — 5:00PM Harry Chang and Government Team 7. Today’s Agenda

17. Publications JOURNALS [P1] C. W. Tan and A. R. Calderbank, "Multiuser Detection of Alamouti Signals," IEEE Transactions on Communications, Vol. 57, No. 7, pp. 2080-2089, Jul. 2009. [P2] C. W. Tan, D. P. Palomar and M. Chiang, "Energy-Robustness Tradeoff in Cellular Network Power Control," IEEE/ACM Transactions on Networking, Vol. 17, No. 3, pp. 912-925, Jun. 2009. [P3] K. Jacobsson, L. L. H. Andrew, A. K. Tang, S. H. Low and H. Hjalmarsson, "An Improved Link Model for Window Flow Control and Its Application to FAST TCP, " in IEEE Transactions on Automatic Control, March 2009. [P4] Chen, L., T. Cui and S. H. Low, " A Game-theoretic Framework for Medium Access Control," IEEE Journal of Selected Areas in Communications, 26(7):1116-1127, September 2008. [P5] Chen, L., S. H. Low and J. C. Doyle, "Random Access Game and Medium Access Control Design," IEEE/ACM Transactions on Networking, submitted 2008. [P6] Chen, L., T. Ho, M. Chiang, S. H. Low and J. C. Doyle, "Congestion Control for Multicast Flows with Network Coding," IEEE Transactions on Information Theory, submitted 2008. [P7] Venkat Anantharam,``Counterexamples to a proposed Stam inequality on finite groups," IEEE Transactions on Information Theory, submitted August 2009.

18. Publications JOURNALS [P8] Y. Cai, Patrick P. C. Lee, W. Gong, D. Towsley. “Analysis of Traffic Correlation Attacks on Router Queues,” under review J. Computer Networks. [P9] B. Jiang, R. Brockett, W. Gong, D. Towsley. “Stochastic differential equations for power law behaviors”, submitted to J. Applied Probability. [P10] W. Gauvin, B. Ribeiro, B. Liu, D. Towsley, J. Wang. “Measurement and gender-specific analysis of user publishing characteristics on MySpace,” to appear in IEEE Network. [P11] B. Ribeiro, D. Towsley. “Estimating and Sampling Graphs with Multidimensional Random Walks,” arXiv:1002.1751, under sumission. [P12] L. Ying, R. Srikant D. Towsley, “Cluster-Based Back-Pressure Routing Algorithm,” submitted to IEEE/ACM Trans. on Networking. (Collaborative effort.) [P13] Libin Jiang and Jean Walrand, “A Distributed CSMA Algorithm for Throughput and Utility Maximization in Wireless Networks,” to appear in IEEE/ACM Transactions on Networking. [P14] L. Jiang, D. Shah, J. Shin, J. Walrand, “Distributed Random Access Algorithm: Scheduling and Congestion Control,” to appear in IEEE Transactions on Information Theory.

19. Publications CONFERENCES [C1] Javad Lavaei, John Doyle and Steven Low, "Congestion Control Algorithms from Optimal Control Perspective," IEEE Conference on Decision and Control, Dec 2009. [C2] K. Jacobsson, L. L. H. Andrew and A. Tang, "Stability and Robustness Conditions using Frequency Dependent Half Planes," IEEE Conference on Decision and Control, Dec 2009.[ C3] M. Wang, C. W. Tan, A. Tang and S. H. Low, "How Bad is Single Path Routing? " Proc. IEEE GLOBECOM, Honolulu, Hawaii, Nov 30-Dec 4, 2009. [C4] C. W. Tan, M. Chiang and R. Srikant, "Optimal Power Control and Beamforming in Multiuser Downlink Systems," Proc. Asilomar Conference on Signals, Systems and Computers, Monterey, CA, Nov 2009. [C5] W. Song, M. Krishnan, and A. Zakhor, “Adaptive Packetization for Error-Prone Transmission over 802.11 WLANs with Hidden Terminals,” IEEE International Workshop on Multimedia Signal Processing, Rio de Janeiro, Brazil, October 2009. [C6] M. Krishnan, S. Pollin and A. Zakhor, "Local Estimation of Collision Probabilities in 802.11 WLANs With Hidden Terminals," IEEE Globecom 2009 Wireless Networking Symposium (GC'09-WNS), Honolulu, HI, December 2009. [C7] Libin Jiang and Jean Walrand, "Utility-Maximizing Scheduling for Stochastic Processing Networks," Forty-Seventh Annual Allerton Conference, Illinois, USA September 2009 [C8] Libin Jiang and Jean Walrand, "Convergence and Stability of a Distributed CSMA Algorithm for Maximal Network Throughput," IEEE Conference on Decision and Control, Dec 2009.

20. Publications CONFERENCES [C9] L. Jiang and J. Walrand, "A Distributed CSMA Algorithm for Throughput and Utility Maximization in Wireless Networks," Forty-Sixth Annual Allerton Conference, Illinois, USA September 23-26, 2008. [C10] L. Jiang and J. Walrand, "Approaching Throughput-Optimality in a Distributed CSMA Algorithm: Collisions and Stability," Mobihoc 2009, New Orleans, LA, May 2009. (Best Student Theory Presentation.) [C11] J. Lee and J. Walrand, "Reliable relaying with uncertain knowledge," Game Theory for Networks, vol., no., pp.82-87, 13-15 May 2009. [C12] C. W. Tan, M. Chiang and R. Srikant, "Maximizing Sum Rate and Minimizing MSE on Multiuser Downlink: Optimality, Fast Algorithms, and Equivalence via Max-min SIR," Proc. IEEE ISIT, Seoul, South Korea, Jun 28-Jul 3, 2009. [C13] Jayakrishnan Nair and Steven H Low, "Optimal Job fragmentation (Extended Abstract)", The Eleventh Workshop on Mathematical Performance Modeling and Analysis, Seattle, WA, June 2009; Also in Performance Evaluation Review, 2009. [C14] C. W. Tan, M. Chiang and R. Srikant, "Fast Algorithms and Performance Bounds for Sum Rate Maximization in Wireless Networks," Proc. IEEE INFOCOM, Rio de Janerio, Brazil, Apr 20-25, 2009. [C15] M. Suchara, L. L. H. Andrew, R. Witt, K. Jacobsson, B. P. Wydrowski, and S. H. Low, "Implementation of Provably Stable MaxNet," in Proc. of BROADNETS 2008, London, UK, September 2008.

21. Publications CONFERENCES [C16] S. Xiao, W. Gong, D. Towsley. “Secure Wireless Communication with Dynamic Secrets”, INFOCOM 2010. (1 of 3 best paper award finalists out of 1535 submissions). [C17] J. Tan, W. Wei, B. Jiang, N.B. Shroff. “Can Multi-Path Mitigate Power Law Delays? -- Effects of Parallelism on Tail Performance,” ITC’22, Sept. 2010. (Collaborative effort.) [C18] B. Ribeiro, W. Gauvin, B. Liu, D. Towsley. "On MySpace Account Spans and Double Pareto-Like Distribution of Friends", IEEE Infocom 2010 Network Science Workshop. [C19] H. Zhao, C.H. Xia, Z. Liu, D. Towsley. "Distributed Resource Allocation for Synchronous Fork and Join Processing Networks", IEEE Infocom Mini-conference, March, 2010. [C20] H. Zhao, C.H. Xia, Z. Liu, D. Towsley. “A Unified Modeling Framework for Distributed Resource Allocation of General Fork and Join Processing Networks,” ACM SIGMETRICS 2010, June 2010. [C21] L. Jiang and J. Walrand, “Distributed Protocols for Wireless Networks,” Keynote, WiOpt, June 2010. [C22] Libin Jiang, Jian Ni, R. Srikant, and Jean Walrand, "Performance Bounds of Distributed CSMA Scheduling," (invited), Information Theory and Application Workshop, UCSD, Feb 2010. (Collaborative effort.)