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T-Labs Networking Lecture Series

Contact person: Birgit Hohmeier-Touré

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T-Labs Networking Lecture Series

Abstracts

2016

Telco Innovation at Home
Speaker:
Dina Papagiannaki
Type:
Networking Lecture Series (NLS)
Time:
21 April 2016
11:00–12:00
Place:
TU Berlin, Marchstr. 23, Room: MAR 4.033
Abstract:
Connectivity services have been the focus of tremendous innovation in the recent past. The majority of such innovation, however, has primarily targeted mobile devices, despite the ever growing interest around home services. In this talk I am going to describe different types of innovation that I consider interesting for residential users and why they have or have not succeeded. The fundamental question is “What does it actually take to create interesting, novel user experiences for residential users?”. In the talk I am going to focus on constraints, but also opportunities that could create meaningful value added services for the place that we love to call our home.
Bio:
Konstantina (Dina) Papagiannaki is the director of Research at Telefonica Research and Development in Barcelona. Prior to that she was a senior researcher at Intel Labs; from 2004 until the end of 2006 in Cambridge, UK and from 2007 until 2011 in Pittsburgh, USA. From the beginning of 2000 until the end of 2003 she was a member of the IP Group at the Sprint Advanced Technology Labs. She got awarded her PhD from the Computer Science Department of University College London (UCL) in March 2003, receiving the Distinguished Dissertations Award 2003. She got her first degree in Electrical and Computer Engineering at the National Technical University of Athens (NTUA) in October 1998. She has chaired the technical program committee of the premier conferences in her field, authored more than 60 peer reviewed papers, authored a book on the design and management of large-scale IP networks through Cambridge University Press, has 1 pending and 5 awarded patents, and has received the best paper awards at ACM Mobicom 2009, ACM IMC 2013, and ACM CoNEXT 2013. She has held an adjunct faculty position in the Computer Science Department at Carnegie Mellon University from 2007 until 2011, and in 2008 she received the rising star award of the computer networking community of ACM. She has participated as an expert in panels for the Federal Commission of Communications, the National Telecommunications and Information Agency, and the National Science Foundation of the U.S.A, as well as the Association of Computing Machinery. In 2015 she was awarded the title of ACM Distinguished Scientist.

2013

Randomness and Wireless Security
Speaker:
   Paul Barford (University of Wisconsin - Madison)
Type:
Networking Lecture Series (NLS)
Time:
22 March 2013
15:30–16:30
Place:
Auditorium 2
(TEL 20)
Abstract:
The availability of accurate and timely maps of the Internet would be a compelling starting point for diverse research topics such as assessing infrastructure vulnerabilities, understanding routing behavior, and analyzing application performance. However, despite the many and varied efforts over the years, there remains no central repository of accurate Internet maps. In this talk, I will describe the challenges in assembling maps of Internet topology based on standard data sources. I will also describes Internet Atlas, a new repository and visualization portal of the physical interconnection structure of the Internet that is under construction at the University of Wisconsin. The repository is populated using web-based information extraction to identify primary source data such as maps and other repositories of service provider network information. The repository currently contains over 8K PoP locations and nearly 13K links for over 275 networks (including all tier 1 providers) around the world. The openly available web portal is based on the widely-used ArcGIS geographic information system, which enables visualization and diverse spatial analyses of the data. To demonstrate the utility of the repository, I will describe two case studies: a first-of-it's kind analysis of physical link distances and an analysis of natural disaster threats to Internet infrastructure.
Bio:
Paul Barford is a professor of Computer Sciences at the University of Wisconsin - Madison. He was a visiting professor at the University of Cambridge and an EPSRC Visiting Fellow in 2011. He was the founder and former CEO of Nemean Networks, LLC, a network security startup company that was acquired by Qualys, Inc. in 2010. His research interests are in Internet measurement and analysis, Internet security, and sustainable networking. Prof. Barford has many highly-cited research papers, and has served on numerous panels, organizing committees, and program committees (ACM SIGCOMM '13 TPC co-chair, ACM SIGMETRICS '10 TPC co-chair, and ACM IMC '06 TPC chair). He has served as an associate editor for IEEE/ACM Transactions on Networking, on the board of directors of the National Lambda Rail, and on technical advisory boards of companies. He is an NSF CAREER award winner and senior member of the ACM and IEEE.
Randomness and Wireless Security
Speaker:
   Don Towsley (U. Massachusetts)
Type:
Networking Lecture Series (NLS)
Time:
27 February 2013
15:00–16:00
Place:
Auditorium
(TEL 20)
Abstract:
The wireless media is a rich source of randomness. In this talk we focus on two problems in securing wireless communication. In the first part we describe a practical way to harness this randomness to provide and/or improve the security of wireless communications. We introduce the notion of "dynamic secrets", information shared by two parties, Alice and Bob, engaged in communication and not available to an adversary, Eve. The basic idea is to dynamically generate a series of secrets from inevitable transmission errors and other random factors present in wireless communications. These dynamic secrets exhibit interesting security properties and offer an alternative to or complement existing security protocols. As part of the talk we will present a simple algorithm for generating these secrets and using them to update a shared key.
In some situations, Alice and Bob may want not only to secure their communications but even to hide it. In the second part of our talk we focus on the use of randomness to conceal the communications. Here the challenge is for Alice to communicate with Bob without an adversary, Willie the warden ever realizing that the communication is taking place. Specifically, we show that Alice can send Ο(√n) bits to the Bob in n channel uses with probability of detection by Willie less than ε for any ε > 0. Conversely, attempting to transmit more than Ο(√n) bits either results in detection by Willie with probability one or a non-zero probability of decoding error by Bob as n → ∞.
Bio:
Don Towsley holds a B.A. in Physics (1971) and a Ph.D. in Computer Science (1975) from University of Texas. He is currently a Distinguished Professor at the University of Massachusetts in the Department of Computer Science. He has held visiting positions at numerous universities and research labs. His research interests include networks and performance evaluation.
He currently serves on the editorial board of IEEE Journal on Selected Areas in Communications and previously served as Editor-in-Chief of IEEE/ACM Transactions on Networking and on numerous other editorial boards. He has served as Program Co-chair of several conferences including INFOCOM 2009.
He has received numerous achievement awards including the 2007 IEEE Koji Kobayashi Award, and numerous paper awards including a 2008 ACM SIGCOMM Test-of-Time Paper Award and the 2012 ACM SIGMETRICS Test-of-Time Award. Last, he has been elected Fellow of both the ACM and IEEE.

2012

Big Data Analytics in Practice
Speaker:
Pietro Michiardi (EURECOM)
Type:
Networking Lecture Series (NLS)
Time:
10 July 2012
15:00–16:00
Place:
Auditorium 1
(TEL 20)
Abstract:
In this talk, we will first overview the MapReduce system and programming model (and its open source incarnation, Hadoop). We will then discuss the EC-Funded BigFoot project, with the goal of illustrating the main objectives and stimulating discussions for possible collaboration between our groups. Finally, I will spend some time discussing the current research activity in my group, that cover systems and tools for large-scale network data processing, and size-based scheduling protocols for parallel systems a-la MapReduce.
Bio:
Pietro Michiardi received his M.S. in Computer Science from EURECOM and his M.S. in Electrical Engineering from Politecnico di Torino. Pietro received his Ph.D. in Computer Science from Telecom ParisTech (former ENST, Paris). Today, Pietro is an Assistant Professor of Computer Science at EURECOM, where he leads the Distributed System Group, which blends theory and system research focusing on large-scale distributed systems (including data processing and data storage), and scalable algorithm design to mine massive amounts of data. Additional research interests are on system, algorithmic, and performance evaluation aspects of computer networks and distributed systems.
Online Privacy: From Users to Markets to Deployment
Speaker:
Vijay Erramilli, Telefonica Digital, Barcelona
Type:
Networking Lecture Series (NLS)
Time:
26 April 2012
16:00–17:00
Place:
Consilium
(TEL 1315)
Abstract:
One of the main reasons for the rise of online services, and indeed the wide scale adoption of the Internet has been the 'services-for-free' model. Popular online services like search, email social networks etc are offered for free to users, and in return personal information (PI) of users is collected and monetized primarily via online advertisements. The collection and exploitation of PI of users has attracted the attention of privacy advocates, regulatory bodies and of late, the mainstream media as well. However, even as many different privacy preserving solutions have been proposed, none of them have been adopted for various reasons, while the situation on the ground vis-a-vis erosion of privacy has been getting worse. In this talk, i'll describe a different approach to online privacy, via the lens of economics. I'll first describe the setup and the results of a large scale user study where the purpose is to extract the monetary value users attach to different types of their personal information online. The results point to a market based solution towards privacy. I'll then describe a solution called Transactional privacy that tries to realise a market for personal information. However, proposing a solution for privacy is merely half the matter. I'll then discuss the conditions necessary for various parties to adopt a privacy solution such as the market, and discuss the road to deployment. In order to study our solution and deployment strategies, we used large datasets from millions of users.
Bio:
Vijay Erramilli is a permanent staff member of the research team at Telefonica Digital, Barcelona. He obtained his PhD from Boston University in Dec. 2008, working with Prof. Mark Crovella and has been with Telefonica since then. During his PhD, he worked with researchers from Technicolor Paris and Intel Research. His primary research interests are network measurements and algorithms. He has worked on various problems in mobile networks, social networks and of late online privacy.
10 Years of Multiuser MIMO
Speaker:
Giuseppe Caire, University of Southern California, USA
Type:
Networking Lecture Series (NLS)
Time:
1 March 2012
12:00–13:00
Place:
Auditorium 1
(TEL 20)
Abstract:
About 10 years ago, some pioneering work including my own unveiled the capacity of the vector Gaussian broadcast channel, where a transmitter communicates independent messages to several receivers and each node has multiple antennas. This model is instrumental for the theoretical understanding of the downlink of a cellular system with multiple-antenna base stations. From an operational viewpoint, the main outcome of this research is that an M-antenna base station communicating to K > M users can achieve a sum throughput that scales as M log SNR, which is the same as if the K users were allowed to perfectly cooperate as a single giant point to point MIMO channel. This opens the door to achieving unprecedented system spectral efficiencies, by simply increasing the number of jointly processed antennas at the base station, or at clusters of base stations connected to a joint processor through sufficiently high rate backhaul links. Remarkably, despite these promises, after 10 years of research, several award winning papers, and significant progresses in the understanding of several aspects of multiuser MIMO, the implementation of such schemes is not at the top of the priority list of current cellular standardization (LTE/3GPP).

In this talk, I am going to review the state of the art on multiuser MIMO, present some recent results, and try to explain why industry has been extremely reluctant to embrace this technology. In contrast, I will provide evidence that a well-designed system that places multiuser MIMO at the center of the physical layer and MAC layer design can achieve very large gains with respect to the current 4G/LTE standards. In addition, I will present some experimental results developed in the USC Ming-Hsieh Department of Electrical Engineering Software-Defined Radio lab, showing the feasibility of multiuser MIMO in a distributed setting, where different base stations cooperate to form a distributed MIMO transmitter and serve simultaneously different users.
Bio (excerpt):
Giuseppe Caire has been assistant professor in Telecommunications at the Politecnico di Torino in 1995-1997, associate professor at the University of Parma, Italy, in 1997-1998 and professor at the Eurecom Institute, Sophia-Antipolis, France, in 1998-2005. He joined the EE Department of the Viterbi School of Engineering, USC, in August 2005.
Backlog-Based Random Access in Wireless Networks: Fairness, Delay and Stability Issues
Speaker:
Sem Borst, Bell Labs Alcatel-Lucent & Eindhoven University of Technology
Type:
Networking Lecture Series (NLS)
Time:
21 February 2012
15:00–16:00
Place:
Auditorium 1
(TEL 20)
Abstract:
We explore the spatio-temporal fairness properties and congestion dynamics of wireless networks with backlog-based random-access mechanisms.
While relatively simple and inherently distributed in nature, suitably designed backlog-based access schemes provide the striking capability to match the optimal throughput performance of centralized scheduling algorithms in a wide range of scenarios.
We show that the specific type of activation rules for which maximum stability has been established, may however yield excessive backlogs and delays.
More aggressive/persistent access schemes have the potential to improve the delay performance, but do not offer any universal maximum-stability guarantees.

In order to gain qualitative insights and examine stability properties we will investigate fluid limits where the system dynamics are scaled in space and time.
As it turns out, several distinct types of fluid limits can arise, ranging from ones with smooth deterministic features, to others which exhibit random oscillatory characteristics, depending on the topology of the network, in conjunction with the form of the activity functions.
As we will show, these qualitatively different regimes are closely related to short-term fairness properties and mixing times for random-access mechanisms with fixed activation rates.
It turns out that more aggressive access schemes continue to provide maximum stability in some networks, e.g. complete interference graphs.
In other topologies however such schemes can drive the system into inefficient states and thus cause instability.
Simulation experiments are conducted to illustrate and validate the analytical results.

Note: based on joint work with Niek Bouman (TU/e), Javad Ghaderi (UIUC), Johan van Leeuwaarden (TU/e), Alexandre Proutiere (KTH), Patrick Thiran (EPFL), Peter van de Ven (IBM), Phil Whiting (Bell Labs), Alessandro Zocca (TU/e)
Bio:
Sem Borst is professor of Stochastic Operations Research at Eindhoven University of Technology and also affiliated with the Mathematics of Networks & Systems Research Department of Bell Labs Alcatel-Lucent in Murray Hill, USA.
His main research interests are in the area of performance evaluation and resource allocation algorithms for communication networks.
He has published over a hundred refereed papers and holds 16 patents in the domain of networking and wireless communications.
Sem serves or has served on the editorial boards of several journals, such as IEEE/ACM Transactions on Networking, Performance Evaluation, Queueing Systems and Wireless Networks.
He served as program committee co-chair for ACM SIGMETRICS 2005 and ITC 22, and has served on various further program committees, such as ACM CoNext, ACM MobiHoc, IEEE Infocom and IFIP Performance.
Sem was (co-)recipient of the best-paper awards at SIGMETRICS/Performance 1992 and IEEE Infocom 2003, the 2001 Yosef Levy Prize, and the 2005 Van Dantzig Prize.
Further information:
Speaker's website at TU/e

2011

Internet privacy: It is not getting better
Speaker:
Balachander Krishnamurthy, AT&T Labs–Research
Type:
Networking Lecture Series (NLS)
Time:
1 November 2011
15:00–16:00
Place:
Auditorium 1
(TEL 20)
Abstract:
Internet privacy has become a hot topic recently with both the advent of Online Social Networks and a significant amount of publicity related to privacy. For the last few years we have been examining the leakage of privacy on the Internet: how information related to individual users is aggregated as they browse seemingly unrelated Web sites. Our results show increasing aggregation of user-related data by a steadily decreasing number of entities.
I will present results from three studies on leakage of personally identifiable information (PII) via Online Social Networks (both traditional and mobile OSNs) and popular non-OSN sites. I will also present the current status of both technical and non-technical attempts to ameliorate the problem.
Bio:
Balachander Krishnamurthy is a member of technical staff at AT&T Labs–Research. His focus of research of is in the areas of Internet privacy, Online Social Networks, and Internet measurements. He has authored and edited ten books, published over 80 technical papers, holds twenty nine patents, and has given invited talks in over thirty countries.
He co-founded the successful Internet Measurement Conference and the Workshop on Online Social Networks. He has been on the thesis committee of several PhD students, collaborated with over seventy five researchers worldwide, and given tutorials at several industrial sites and conferences.
His most recent book "Internet Measurements: Infrastructure, Traffic and Applications" (525pp, Wiley, with Mark Crovella), was published in July 2006 and is the first book focusing on Internet Measurement. His previous book "Web Protocols and Practice: HTTP/1.1, Networking Protocols, Caching, and Traffic Measurement" (672 pp, Addison-Wesley, with Jennifer Rexford) is the first in-depth book on the technology underlying the World Wide Web, and has been translated into Portuguese, Japanese, Russian, and Chinese.
Bala is homepageless and not on any OSN but many of his papers can be found at www.research.att.com/~bala/papers.
Distributed Computing: Theory meets Practice
Schedule of the NLS Workshop, July 20, 2011
Time
Speaker
Title
09:30–10:45
Roger Wattenhofer, ETH Zürich
Theory Meets Practice: It’s about Time
10:45–12:00
Andréa Richa, Arizona State University
Jamming-Resistant Wireless Network MAC Protocols
12:00–13:30
Lunch break
13:30–14:45
Christian Scheideler, Universität Paderborn
Approximate Duality of Multicommodity Multiroute Flows and Cuts
All talks will take place in Auditorium 3 (TEL 20), Ernst-Reuter-Platz 7, 10555 Berlin.
Data-driven Behaviour-based Networked Mobile Communities
Speaker:
Ahmed Helmy, University of Florida
Type:
Networking Lecture Series (NLS)
Time:
14 July 2011
16:00–17:00
Place:
Auditorium 2
(TEL 20)
Abstract:
The future of social networking is in the mobile world. Future network services are expected to center around human activity and behavior. Wireless networks (including ad hoc, sensor networks and DTNs) are expected to grow significantly and accommodate higher levels of mobility and interaction. In such a highly dynamic environment, networks need to adapt efficiently (performance-wise) and gracefully (correctness and functionality-wise) to growth and dynamics in many dimensions, including behavioral and mobility patterns, on-line activity and load. Understanding and realistically modeling this multi-dimensional space is essential to the design and evaluation of efficient protocols and services of the future Internet.
This level of understanding to drive the modeling and protocol design shall be developed using data-driven paradigm. The design philosophy for the proposed paradigm is unique in that it begins by intensive analysis of measurements from the target contexts, which then drive the modeling, protocol and service design through a systematic framework, called TRACE. Components of TRACE include: 1. Tracing and monitoring of behavior, 2. Representing and Analyzing the data, 3. Characterizing behavioral profiles using data mining and clustering techniques, and finally 4. Employing the understanding and insight attained into developing realistic models of mobile user behavior, and designing efficient protocols and services for future mobile societies.
Tracing at a large scale represents the next frontier for sensor networks (sensing the human society). Our latest progress in that field (MobiLib) shall be presented, along with data mining and machine learning tools to meaningfully analyze the data. Several challenges will be presented and novel use of clustering algorithms will be provided. Major contributions to modeling of human mobility (the time variant community model, TVC) will also be discussed.
Finally, insights developed through analysis, mining and modeling will be utilized to introduce and design a novel communication paradigm, called profile-cast, to support new classes of service for interest-aware routing and dissemination of information, queries and resource discovery, trust and participatory sensing (crowd sourcing) in future mobile networks. Unlike conventional - unicast, multicast or directory based - paradigms, the proposed paradigm infers user interest using implicit behavioral profiling via self-monitoring and mining techniques. In order to capture interest, a spatio-temporal representation is introduced to capture users behavioral-space. Users can then identify similarity of interest based on their position in such space.
The proposed profile-cast paradigm will act as enabler to new classes of service, ranging from mobile social networking, and navigation of mobile societies and spaces, to computational health care and education, among others.
Bio:
Dr. Ahmed Helmy is an Associate Professor at the Computer and Information Science and Engineering (CISE) Department at the University of Florida (UF). He received his Ph.D. in Computer Science 1999 from the University of Southern California (USC), M.Sc. in Electrical Engineering (EE) 1995 from USC, M.Sc. in Engineering Mathematics in 1994 and B.Sc. in Electronics and Communications Engineering 1992 from Cairo University, Egypt. He was a key researcher in the Network Simulator NS-2 and Protocol-Independent Multicast (PIM) projects at USC/ISI from 1995 to 1999. Before joining UF in 2006, he was on the Electrical Engineering-Systems Department faculty at USC starting Fall 1999, where he founded and directed the Wireless and Sensor Networks Labs.
In 2002, he received the NSF CAREER Award for his research on resource discovery and mobility modeling in large-scale wireless networks (MARS). In 2000 he received the Zumberge Award, and in 2002 he received the best paper award from the IEEE/IFIP MMNS Conference. In 2003 he was the Electrical Engineering nominee for the USC Engineering Jr. Faculty Research Award, and a nominee for the Sloan Fellowship. In 2004 and 2005 he got the best faculty merit ranking at the Electrical Engineering department at USC. He was a winner in the ACM MobiCom 2007, a finalist in 2008 SRC competitions, and a 2nd place winner in ACM MobiCom WiNTECH demo competition 2010. He is leading (or has led) several NSF funded projects including MARS, STRESS, ACQUIRE and AWARE.
His research interests include design, analysis and measurement of wireless ad hoc, sensor and mobile social networks, mobility modeling, multicast protocols, IP mobility and network simulation. He has published over 150 journal articles, conference papers and posters, book chapters, IETF RFCs and Internet drafts. His research is (or has been) supported by grants from NSF, Intel, Cisco, DARPA, NASA, Nortel, HP, Pratt & Whitney, Siemens and SGI.
Dr. Helmy is an area editor of the Ad hoc Networks Journal - ElSevier (since 2004), and an area editor of the IEEE Computer (since 2010). He is serving (or has served as) the program co-chair for ACM MSWiM 2011, and ACM MobiCom CHANTS workshop 2011, co-chair of AdhocNets 2011, honorary program chair of IEEE/ACM IWCMC 2011, general chair of IWCMC 2010, vice-chair of IEEE MASS 2010, plenary panel chair of IEEE Globecom 2010, co-chair of IEEE Infocom Global Internet (GI) workshop 2008, and IFIP/IEEE MMNS 2006, vice-chair for IEEE ICPADS 2006, IEEE HiPC 2007, and local & poster chair for IEEE ICNP 2008 and 2009. He is ACM SIGMOBILE workshop coordination chair (for MobiCom, Mobihoc, Mobisys, Sensys) (since 2006). He has served on numerous committees of IEEE and ACM conferences on networks. He is a member of IEEE (Computer and Communications Societies) and ACM (Sigmobile and Sigcomm Groups).
Integrity and Consistency for Untrusted Service
Speaker:
Christian Cachin, IBM Research – Zurich
Type:
Networking Lecture Series (NLS)
Time:
22 June 2011
16:00–17:00
Place:
Auditorium 1
(TEL 20)
Abstract:
A group of mutually trusting clients outsources an arbitrary computation service to a remote provider, which they do not fully trust and that may be subject to attacks. The clients do not communicate with each other and would like to verify the integrity of the stored data, the correctness of the remote computation process, and the consistency of the provider's responses.
We present a novel protocol that guarantees atomic operations to all clients when the provider is correct and fork-linearizable semantics when it is faulty; this means that all clients which observe each other's operations are consistent, in the sense that their own operations, plus those operations whose effects they see, have occurred atomically in same sequence. We describe how this protocol generalizes previous approaches that provided such guarantees only for outsourced storage services.
Bio:
Christian Cachin graduated with a Ph.D. in Computer Science from ETH Zurich in 1997. He was a postdoctoral researcher at the MIT Laboratory for Computer Science from 1997-1998. Since 1998 he has been a Research Staff Member at the IBM Research - Zurich, involved with research projects in the fields of cryptology and distributed systems. In 2009 he was a visiting researcher at the Ecole Polytechnique Federale de Lausanne (EPFL).
His current research interests are the security of storage systems, secure protocols for distributed systems, and cryptography. He contributed to the OASIS Key Management Interoperability Protocol (KMIP) standard and is concerned with the security of cloud computing in the EU-funded TClouds - Trustworthy Clouds project.
Ressources:
Talk slides (PDF, 545,7 KB)
Quantifying Location Privacy
Speaker:
George Theodorakopoulos, EPFL
Type:
Networking Lecture Series (NLS)
Time:
28 April 2011
16:00–17:00
Place:
Auditorium 1
(TEL 20)
Abstract:
The popularity of personal communication devices leads to serious concerns about privacy in general, and location privacy in particular. As a response to these issues, a number of Location-Privacy Protection Mechanisms (LPPMs) have been proposed during the last decade. However, their assessment and comparison remains problematic because of the absence of a systematic method to quantify them. In particular, the assumptions about the attacker's model tend to be incomplete, with the risk of a possibly wrong estimation of the users' location privacy.
We address these issues by providing a formal framework for the analysis of LPPMs; the framework captures, in particular, the prior information that might be available to the attacker, and various attacks that he can perform. By formalizing the adversary's performance, we propose and justify the right metric to quantify location privacy. We find that popular privacy metrics, such as k-anonymity and entropy, do not correlate well with the success of the adversary in inferring users' locations.
Bio:
George Theodorakopoulos is a senior researcher at EPFL working with Prof. Jean-Yves Le Boudec. He received his B.Sc. at the National Technical University of Athens (NTUA), Greece, and his M.Sc. and Ph.D. at the University of Maryland, in 2002, 2004 and 2007, respectively.
His research is on network security, privacy, and trust. He has received the best paper award at WiSe'04, the 2007 IEEE ComSoc Leonard Abraham prize, and he has co-authored the book "Path Problems in Networks" on algebraic (semiring) generalizations of shortest path algorithms and their applications to networking problems.

2010

Cutting the Electrical Bill for Internet-Scale Systems
Speaker:
Bruce Maggs, Duke University and Akamai Technologies
Type:
Networking Lecture Series (NLS)
Time:
10 December 2010
14:00–15:00
Place:
TEL 1118
Abstract:
This talk shows how operators of Internet-scale distributed systems, such as Google, Microsoft, and Akamai can reduce electricity costs (but not necessarily energy consumption) by dynamically allocating work among data centers in response to fluctuating energy prices. The approach applies to systems consisting of fully replicated clusters of servers installed in diverse geographical locations where energy can be purchased through spot markets. Using historical energy prices for major energy markets in the United States, as well as usage data from Akamai's content delivery network, we should how much can be saved now, and what might be saved in the future given server technology trends.
Joint work with Asfandyar Qureshi, Rick Weber, Hari Balakrishnan, and John Guttag.
Bio:
Bruce Maggs is a professor in the Department of Computer Science at Duke University. He was instrumental in starting Akamai Technologies, where as the first Vice President for Research and Development he led all engineering efforts. Since returning to academia he has retained a part-time role at Akamai as Vice President for Research. Professor Maggs's research focuses on how to build large distributed systems. He serves on the steering committees of the Internet Measurement Conference and the HotNets Workshop, and has served on the program committees of the STOC, SODA, SPAA, PODC, SIGCOMM, NSDI, and IMC conferences.
Signature-Free Broadcast-Based Intrusion Tolerance: Never Decide a Byzantine Value
Speaker:
Michel Raynal, IRISA / University of Rennes 1
Type:
Networking Lecture Series (NLS)
Time:
25 November 2010
11:00–12:00
Place:
Consilium
(TEL 1315)
Abstract:
Providing application processes with strong agreement guarantees despite failures is a fundamental problem of fault-tolerant distributed computing. Correct processes have not to be ``polluted'' by the erroneous behavior of faulty processes. This paper considers the consensus agreement problem in a setting where some processes can behave arbitrarily (Byzantine behavior). In such a context it is possible that Byzantine processes collude to direct correct processes to decide on a ``bad'' value (a value proposed only by faulty processes).
The talk will present several contributions (joint work with Achour Mostéfaoui). It will first present a family of consensus algorithms in which no bad value is ever decided by correct processes. These processes always decide a value they have proposed (and this is always the case when they all propose the same value) or a default value. These algorithms are called " intrusion-free "consensus algorithms. To that end, each consensus algorithm is based on an appropriate underlying broadcast algorithm. One of these abstractions, called "validated broadcast" is new and allows the design of a resilience-optimal consensus algorithm (i.e., it copes with up to t < n/3 faulty processes where n is the total number of processes). All proposed consensus algorithms assume that the underlying system is enriched with additional computational power provided by a binary Byzantine consensus algorithm. The talk will also present a resilience-optimal randomized binary consensus algorithm based on the validated broadcast abstraction. An important feature of all these algorithms lies in the fact that they are signature-free (and hence particularly efficient).
Bio:
Michel Raynal has been a professor of computer science since 1981. At Inria, he founded a research group on Distributed Algorithms in 1983. He has been Principal Investigator of a number of research grants in these areas, and has been invited by many universities all over the world to give lectures and tutorials on distributed algorithms and fault-tolerant distributed computing systems. He belongs to the editorial board of several international journals. Professor Michel Raynal has published more than 95 papers in journals and more than 195 papers in conferences. He has also written seven books devoted to parallelism, distributed algorithms and systems (MIT Press and Wiley).
Gossiping: Checks and Balances
Speaker:
Maarten van Steen, Vrije Universitet
Type:
Networking Lecture Series (NLS)
Time:
13 October 2010
11:00–12:00
Place:
Consilium
(TEL 1315)
Abstract:
In the past years, researchers at VU University have been paying a lot of attention to gossip-based distributed systems, be they wired or wireless. While doing so, we have been taking several perspectives on gossiping, notably as a facilitator for designing robust self-organizing systems, as a subject for formal modeling and analysis, and as technique that suffers from very basic practical issues such as security attacks. In this talk, I will provide a brief overview of the checks and balances that we have been trying to find between gossiping systems, their formal modeling, and dealing with practicalities such as security. In doing so, I will provide a general framework that can be used for capturing a large class of existing gossiping protocols, and using this framework demonstrate its applicability for systems design and analysis. Next to examples of fully decentralized gossiping systems, I will touch upon the difficulties of conducting formal analyses in order to optimize performance, but also illustrate how easy it may be to break a gossiping protocol and what it may take to regain robustness. As I will also make clear, most of the lessons that can be drawn from our research are not unique to gossiping, but are equally well applicable to many large-scale decentralized systems.
Bio:
Maarten van Steen is full professor at VU University Amsterdam, leading a research team on large-scale distributed systems. His research, which is experimental by nature, covers very large Internet-based systems as well as systems running on wireless networks of resource-constrained devices such as sensor nodes. Together with Andrew Tanenbaum he is co-author of a textbook on distributed systems, and has recently completed an introductory textbook on graph theory and complex networks.
An Overview of the OpenAirInterface.org Platform Initiative
Speaker:
Raymond Knopp, Eurecom, Sophia Antipolis, France
Type:
Networking Lecture Series (NLS)
Time:
28 September 2010
16:00 – 17:00
Place:
Consilium
(TEL 1315)
Abstract:
We provide an overview of the OpenAirInterface.org experimental platform which targets innovation in access-layer technologies for next-generation wireless communication systems. OpenAirInterface.org is an open-source initiative comprising both software development environments and hardware prototypes for broadband radio communications. It comprises both real-time full-RF solutions as well as emulation environments. All developments are made available in the public-domain through a public license. The current hardware platform supports two-way multiple-input multiple-output (MIMO) transceivers with channel bandwidths up to 20 MHz and can handle LTE/WiMAX-like waveforms in real-time. We give an overview of both the full x86-based software-radio and embedded FPGA-based system-on-chip (SoC) architectures that are used. OpenAirInterface.org includes a reference PHY layer based on the evolving LTE/LTE-A system and, in addition, a MAC-layer which can be configured for both cellular and mesh (relay-based) topologies. These can be interconnected with standard layer-2.5/layer-3 protocols (IPv4/IPv6/MPLS) bundled with the Linux operating system in order to provide an environment for reduced-scale test deployments of experimental wireless networks. We report on recent field trials for next-generation rapidly-deployable wireless networks in support of civil protection services and 850 MHz LTE networks in rural environments in addition to current developments for future experimental deployments in ongoing FP7 projects.
Bio:
Raymond Knopp is a professor in the Mobile Communications Department at Eurecom, Sophia Antipolis, France. He received the B.Eng. (Honours) and the M.Eng. degrees in Electrical Engineering from McGill University, Montreal, Canada, in 1992 and 1993, respectively. In 1997 he received the PhD degree in communication systems from the Swiss Federal Institute of Technology (EPFL), Lausanne. From 1997-2000 he was a research associate in the Mobile Communications Laboratory (LCM) of the Communication Systems Department of EPFL. His current research and teaching interests are in the area of digital communications, software radio architectures, and implementation aspects of signal processing systems and real-time wireless networking protocols. He participates actively in collaborative research projects related to wireless communications in European framework programmes as well as French National programs. He has a long track record in managing both fundamental and experimental research projects; he is currently project coordinator of FP7 LOLA project, workpackage leader in the NEWCOM++ and @cropolis Networks of Excellence. He is technical coordinator of the OpenAirInterface.org wireless radio platform initiative.
Green Radios for a Sustainable Future Internet
Speaker:
Liesbet van der Perre, IMEC (Interuniversity MicroElectronics Center)
Type:
Networking Lecture Series (NLS)
Time:
27 September 2010
14:00 – 15:00
Place:
Consilium
(TEL 1315)
Abstract:
Until five years ago, research in wireless communications was mainly geared towards offering ever higher data rates and improving coverage. Today however, society appeals to us to tackle the far more fundamental problems. We have indeed become aware that reducing energy consumption and radiation levels will be essential to sustain a further evolution towards viable, ubiquitous connectivity. In this talk, we propose the "double scaling" concept as a key solution to achieve drastic energy savings. This concept targets to exploit both cell and technology downscaling in a mutually reinforcing way. Imec's R&D embarks for the journey towards next generation wireless connecti vity, powered by 'green radios'. Specifically, an introduction will be presented to the following programs:
  • Cognitive reconfigurable radio, opening new horizons in wireless communication
  • 60GHz wireless communication, Boosting high-data-rate short range connectivity
Bio:
Liesbet Van der Perre received the M.Sc. degree in Electrical Engineering from the K.U.Leuven, Belgium, in 1992. The research for her thesis was completed at the Ecole Nationale Superieure de Telecommunications in Paris. She graduated with a PhD in electrical engineering form the same university in 1997. Her work in the past focused on radio propagation modelling, system design and digital modems for high- speed wireless communications. Currently, she is program director for IMEC's green radio program, comprising cognitive reconfigurable radios and mm-wave communications, involving a team of 70 comprising world-class experts and the diversity of 15 nationalities. Also, she is a Professor at the K.U.Leuven.
A Control Theoretic Approach to Distributed Optimal Configuration of 802.11 WLANs
Speaker:
Albert Banchs, University Carlos III of Madrid
Type:
Networking Lecture Series (NLS)
Time:
21 Sepbember 2010
16:00 – 17:00
Place:
Consilium
(TEL 1315)
Abstract:
The optimal configuration of the contention parameters of a WLAN depends on the network conditions in terms of number of stations and the traffic they generate. Following this observation, a considerable effort in the literature has been devoted to the design of distributed algorithms that optimally configure the WLAN parameters based on current conditions. In this work we propose a novel algorithm that, in contrast to previous proposals which are mostly based on heuristics, is sustained by mathematical foundations from multivariable control theory. A key advantage of the algorithm over existing approaches is that it is compliant with the 802.11 standard and can be implemented with current wireless cards without introducing any changes into the hardware or firmware.We study the performance of our proposal by means of theoretical analysis, simulations and a real implementation. Results show that the algorithm substantially outperforms previous approaches in terms of throughput and delay.
Bio:
Albert Banchs got his Telecommunication Engineering degree at the Polytechnical University of Catalonia in 1997, and the PhD from the same university in 2002. His PhD thesis, supervised by Professor Sebastia Sallent, addressed the issue of fairly sharing the network resources among users both in the wired and wireless Internet. Albert Banchs received for his PhD the mention of European Doctor and was awarded by COIT (the spanish official association of Telecommunication Engineers) the ONO prize to the best spanish PhD thesis on Broadband Networks.
From April to December 1997, Albert Banchs worked in the Networks Group of the International Computer Science Institute (ICSI), Berkeley, California. His work at ICSI focused on active networks research. From January to August 1998 he was with the Telefonica I+D Labs in Madrid, Spain, where he was appointed coordinator of an 8-people development team working on the videoconference over IP project. In September 1998 he joined NEC Network Laboratories in Heidelberg, Germany. He started as a Research Staff Member and was promoted to Senior Research Staff Member in April 2001. At NEC, Albert Banchs worked on a number of projects, including multicast over ADSL, DiffServ and 802.11e standardization.
Since October 2003, Dr. Banchs is with the University Carlos III of Madrid, where he currently holds the position of Associate Professor. From 2003 to 2008 he worked on the EU projects Daidalos I and Daidalos II, where he led the activity of QoS over heterogeneous networks. Current major effort is on the EU project CARMEN (CARrier grade MEsh Networks), where he is leading the architecture work. His research interests include performance evaluation and resource allocation in wireless networks.
Load Balancing via Random Local Search and Random Load Oblivious Sampling in Closed and Open Systems
Speaker:
Sarah Lilienthal, University of Cambridge
Type:
Networking Lecture Series (NLS)
Time:
24 August 2010
16:00–17:00
Place:
Auditorium 2
(TEL 20)
Abstract:
The topic of this talk is the analysis of the performance of random load resampling and migration strategies in parallel server systems. Clients initially attach to an arbitrary server, but may switch servers independently at random instants of time in an attempt to improve their service rate. This approach to load balancing contrasts with traditional approaches where clients make smart server selections upon arrival (e.g., Join-the-Shortest-Queue policy and variants thereof). Load resampling is particularly relevant in scenarios where clients cannot predict the load of a server before being actually attached to it. An important example is in wireless spectrum sharing where clients try to share a set of frequency bands in a distributed manner. We first analyze the natural Random Local Search (RLS) strategy. Under this strategy, after sampling a new server randomly, clients only switch to it if their service rate is improved. In closed systems, where the client population is fixed, we derive tight estimates of the time it takes under RLS strategy to balance the load across servers. We then study open systems where clients arrive according to a random process and leave the system upon service completion. In this scenario, we analyze how client migrations within the system interact with the system dynamics induced by client arrivals and departures. We compare the load-aware RLS strategy to a load-oblivious strategy in which clients just randomly switch server without accounting for the server loads. Surprisingly, we show that both load-oblivious and load-aware strategies stabilize the system whenever this is at all possible. We further demonstrate, using large-system asymptotics, that the average client sojourn time under the load-oblivious strategy is not considerably reduced when clients apply smarter load-aware strategies.

This is joint work with A. Ganesh, D. Manjunath, A. Proutiere and F. Simatos.
Bio:
Sarah Lilienthal is a PhD student under the supervision of Frank Kelly at the Statistical Laboratory, University of Cambridge. She received a BA in Mathematics and an MMath from Trinity College, University of Cambridge. Her research focuses on multipath routing and load balancing in stochastic networks. She is winner of the ACM Sigmetrics 2010 Best Paper Award.
Recursion in distributed computing
Speaker:
Eli Gafni, UCLA
Type:
Networking Lecture Series (NLS)
Time:
20 July 2010
16:00–17:00
Place:
Auditorium 2
(TEL 20)
Abstract:
The benefits of developing algorithms via recursion are well known. However, little use of recursion has been done in distributed algorithms, in spite of the fact that recursive structuring principles for distributed systems have been advocated since the beginning of the field. We present several distributed algorithms in a recursive form, which makes them easier to understand and analyze. Also, we expose several interesting issues arising in recursive distributed algorithms. Our goal is to promote the use and study of recursion in distributed algorithms.

Joint Work with Sergio Rajsbaum, UNAM.
Bio:
Eli Gafni is a professor of CS at UCLA. He joined UCLA in 1982, the year he got his PhD in EECS from MIT. He got his Ms.C from University of Illinois at Urbana-Champaign in 1979, and his Bs.C from the Technion, Israel in 1972. He was at the right place at the right time with the emergence of the ARPAnet, and his PhD Thesis is still quoted in the networks community. Alas, his abstraction tendencies got the better of him, and since then through progression of abstractions he is now completely theoretical investigating the limits of Shared-Memory models.


How the Pursuit of Truth Led Me to Selling Viagra®
Speaker:
Vern Paxson, UC Berkeley
Type:
Networking Lecture Series (NLS)
Time:
13 July 2010, 16:00–17:00
Place:
Auditorium 3 (TEL 20)
Abstract:
For an empiricist, at the heart of the pursuit of truth lies measurement. This talk will provide examples drawn from measurement illustrating the enormous changes in the Internet security landscape over the past decade. I will then explain why these changes led to colleagues and me trying our hand at selling Viagra – all for the cause of Science – and what the implications of our experiences tell us about modern cybercrime.
Bio:
Vern Paxson is a Professor in Electrical Engineering and Computer Sciences at the University of California, Berkeley, USA, and also has affiliations with the International Computer Science Institute and the Lawrence Berkeley National Laboratory. His main active research projects are network intrusion detection in the context of Bro, a high-performance network intrusion detection system he developed; network measurement and analysis; and the threat of botnets and the underground economy that they fuel. He is an ACM Fellow and recipient of the 2008 ACM Grace Murray Hopper Award for his work on Internet measurement.

 

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