Despite the broadly title, the seminar will be focused in the notion of max-min fairness (MMF) and its application to routing optimization in communication networks:

1. Basic notions
2. Convex MMF problems
3. Non-convex MMF problems
4. Examples of MMF routing optimization problems

• Dr. Sergey Gorinsky (Senior Researcher, IMDEA Networks)
• Prof. Dr. Arturo Azcorra (Director General for Technology Transfer and Entrepreneurial Development (Spanish Ministry of Science and Innovation)
• Paul Patras (Research Assistant, IMDEA Networks)
• Dr. Mary Luz Mouronte (Division Manager, Telefonica Research, Madrid)
• Dr. Albert Banchs (Deputy Director, IMDEA Networks; Associate Professor, UC3M)
• Prof. Dr. Narasimha Reddy (Cátedra de Excelencia, University Carlos III of Madrid; Visiting Researcher, IMDEA Networks, Madrid; Texas A&M University, USA)
• Alejandro Javier Tosina González (Spanish Representative in ICT Committee – EU Framework Programme; CDTI – Ministry of Science and Innovation)

Location: Basement Floor, “Sala de Audiovisuales”, Room 3.1.S08, Building: Rey Pastor (Library), University Carlos III of Madrid, Avda. Universidad, 30, 28911 Leganes – Madrid
Date: November 11^th, 2009, 15:00 – 18:00
Organization: IMDEA Networks in collaboration with the Higher Polytechnic School, University Carlos III of Madrid, Leganes Campus

The conference will be conducted in English
Advanced registration: rebeca.demiguel imdea.org

Dr. Kenichi Mase, Dr. Toshini Tsuboi and Dr. Hiromi Ueda will visit Institute IMDEA Networkson Monday September 20th and will take the opportunity to present their research lines. The overall talk will last about 45 minutes, including questions and answers, and it will be divided in the following three 15 minute slots:

A great deal of of interesting work was done in the 1970s in generalizing shortest path algorithms to a wide class of semirings also called "path algebras" or "dioids". Although the evolution of Internet Routing protocols does not seem to have taken much inspiration from this work, recent "reverse engineering" efforts have demonstrated that an algebraic approach is very useful for both understanding existing protocols and for exploring the design space of future Internet routing protocols. This course is intended teach participants the basic concepts needed to understand this approach. No previous background will be assumed. 

The first Workshop on "far out" research ideas of the institute is to be held on December 17th, 2010. The purpose of the first edition of this series of workshops is to have researchers from the institute present very innovative ideas that could lead to internal projects or even the offspring of a full line of research. The sessions encourage brain-storming around the ideas presented, in order to help give them shape and evaluate their potential. 

It this talk I will start with a brief overview of the research activities of our group at the University of New South Wales, Sydney, Australia, in the areas of core network switching, body area networking, and security for wireless sensor networks. I will then focus on the specific problem of sizing buffers in core routers, highlighting constraints posed by power consumption and optical storage technology. We investigate the impact of router buffer size on the characteristics of TCP traffic and its co-existence with open-loop traffic. We propose and analyze the efficacy of techniques such as traffic conditioning and forward error correction in managing contention loss in the network core. Finally, we speculate on the feasibility of a future Internet core with near-zero buffers.

The scalability issues the global routing system has been experienc- ing over the past years have raised serious concerns in the Internet community. One of the main culprits for the rapidly growing BGP routing table is the defragmentation process of the address blocks allocated to ASes, also known as prefix deaggreation. The Internet is a complex system and understanding its behavioural evolution is certainly a challenging task. For this reason, the use of eco- nomic models can provide intuitive explanations of the complex interactions between networks that result in the aforementioned phenomenon of prefix deaggreation. In this paper, we propose a game theoretic model to analyze the incentives behind the deag- gregating strategies of the networks. Announcing more-specific prefixes in the Internet impacts the size of the global routing table and increases the network operators’ capital expenditure for rout- ing equipment capable of sustaining the growing Internet. How- ever, we prove that the ASes are driven by fundamental economic reasons towards this type of apparently harming behaviour. We find that by announcing more prefixes the originating network achieves a more predictable traffic pattern and reduces the peak levels of bandwidth consumption. We show that this happens because, both in the equilibrium point and the social welfare point, the cost re- duction achieved by smoothing the traffic distribution outweighs the additional cost incurred by the routing table expansion.

The second Workshop on "far out" research ideas of the institute is to be held on January 19th, 2011. The purpose of the second edition of this series of workshops is to have researchers from the institute present very innovative ideas that could lead to internal projects or even the offspring of a full line of research. The sessions encourage brain-storming around the ideas presented, in order to help give them shape and evaluate their potential.

A frequent problem in settings where a unique resource must be shared among users is how to resolve the contention that arises when all of them must use it, but the resource allows only for one user each time. The application of efficient solutions for this problem spans a myriad of settings such as radio communication networks or databases.

Carrier Sense Multiple Access with Enhanced Collision Avoidance (CSMA/ECA) is a distributed MAC protocol that allows collision-free access to the medium in WLAN. The only difference between CSMA/ECA and the well-known CSMA/CA is that the former uses a deterministic backoff after successful transmissions. Collision-free operation is reached after a transient state during which some collisions may occur. This article shows that the duration of the transient state can be shortened by appropriately setting the contention parameters. Standard absorbing Markov Chain theory is used to describe the behaviour of the system in the transient state and to predict the expected number of slots to reach the collision-free operation.