Seminars
2005
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Seminars
The Networks Group meets regularly throughout the year for informal discussions, presentations, and a reading group. This is an archive of the seminar abstracts and links to the seminar slides for 2003.
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January 14 (Room 214) (first week of term)
Speaker:Jon Crowcroft (Computer Lab, Cambridge)
Title: Scalable Ubiquitous Computing Systems slides (ppt)
Abstract:
We are all acquainted with the Personal Computer. We are less aware of the burgeoning numbers of invisible, embedded computers around us in the fabric of our homes, shops, vehicles and even farms.
They help us command, control, communicate, entertain, and commerce, and these invisible computers are far, far more numerous than their desktop cousins.
The visible face of computing, the ubiquitous PC, is nowadays generally networked. To date, embedded computing systems have been largely used to replace analog control systems (for reasons of price, performance and reliability). Increasingly, however, we will find systems are integrated into a whole.
This will lead to a challenge for Computer Science in the form of system complexity. Complexity is at the core of the skill-set of computer science and engineering, but it is also becoming a key piece of the formalisms used to understand other systems in the natural world, in ecology and biology and in physics. With the Internet as large and organic as it already is, we see a complex set of interactions with graph theory, control theory, economics and game theory, and a number of other disciplines being bought to bear and even extended to understand its behaviour. We also see a set of engineering rules of thumb maturing into design principles, which can be applied to other systems.
Some principles already established in the world of Internet-scale engineering give us hope that we can build systems early (and there are many Ubiquitous Computing projects underway in the UK, EU and world today), with some hope that they will work. However, as systems grow, new problems for performance (stability, availability, etc) will emerge. Critical new areas for concern are the control of multiple resources (scheduling for battery life, randomising timing of events to avoid correlated overload, statistical failure tolerance in very large scale sensor systems). Within the timescales of this challenge, components will even start to draw resources (power) directly from their environment (ambient heat, RF etc), and this has hidden consequences (radio opacity in unusual places for example). The more we look at how such systems will be built, the more we see them vanish into the substance (and ether) around us!
The core of this challenge then, is to abstract out these engineering design principles, and this will be achieved largely through a process of ``build and learn''. This is a natural complement and sister to the challenge to uncover the Science for Global Ubiquitous Computing, which will have descriptive power. We will have prescriptive solutions (patterns) for the mixed reality environment that will form the next phase of development of cyberspace.
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January 21
Speaker:Martin Dodge (CASA, UCL)
Title: See Inside The Cloud : Some Ways to Map the Internet (slides pdf)
Abstract:
What does the internet look like? Conventionally, engineers have
represented it as a cloud, a useful graphic shorthand to mask its
complexity. In my presentation I consider how cartographic maps and graph
visualisations are used to represent whats inside the internet cloud. Maps
are powerful because they do not just represent space, they are also
active in the construction of space inside peoples heads. This is
especially so in the construction of peoples cognitive conceptions of the
internet, as the infrastructure is largely invisible and intangible in
everyday life.
Over the last thirty years or so, a huge range of different maps of the
internet have been produced, with diverse forms and function, from simple
geographic plans of cable routes to complex real-time 3D visualisations.
They have been produced for a number of distinct purposes from planning
network deployment, operational management, to prove academic theories, as
grad student projects, for market research, for setting policy and
monitoring outcomes, and to try to sell things. And, of course, many have
been motivated to map the internet for no particular reason other than
because it is there. There are many different aspects of the internet that
have been mapped from physical infrastructure, logical layers and
protocols, traffic flows, user demographics. The maps cover a range of
different scales from individuals, single buildings up to global scale.
Many of these maps are beautiful and many more are really rather ugly. A
few are actually quite useful, but many more are not very helpful at all.
However, all the maps provide a fascinating picture of what the internet
looks like, or rather they provide some insights into what people think
the internet should look, once the clouds have cleared.
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January 28
Speaker:Joe Touch (ISI)
Title: Virtual Internet Research at the Postel Center (slides(ppt) )
Abstract:
Virtual Internets (VIs) are emerging as a useful tool for managing
shared testbed infrastructure, as well as supporting emerging protocols
and systems. This talk presents the principles of our Virtual Internet
Architecture, and examines its impact on the architecture of end
systems, routers, and protocols. The talk also summarizes related
research exploring the capabilities of VIs and augmenting system
capabilities to support VIs. This includes: the X-Bone system for
automated VI deployment and management; the DynaBone system for
fault-tolerance and performance via multi-layer virtualization; the
NetFS system for providing compartmentalized configuration of network
resources; and the DataRouter system for supporting application-directed
peer networks via a network-layer string rewriting mechanism.
Time permitting, we will also demonstrate TetherNet (adapted VI
technology), a system for Internet subnet leasing that can undo the
effects of NATs, and present a brief summary of our emerging work in
designing components to support an all-optical Internet router.
Bio:
Joseph D. Touch is Director of the Postel Center in the Computer
Networks Division of USC's Information Sciences Institute (ISI). He
received a B.S. with Honors in biophysics and CS from the University of
Scranton in 1985, an M.S. in CS from Cornell University in 1987, and a
Ph.D. in CS from the University of Pennsylvania in 1992. He joined ISI
in in 1992, and his current projects include automatic networks, virtual
networks (NetFS, X-Tend), and optical Internets. His research interests
include Internet protocols, network architecture, high-speed &
low-latency nets, network device design, and experimental network
analysis. His past projects range from gigabit LANs (Atomic-2), NIC
design (PC-Atomic), and multicast web caching (LSAM), to overlay
networks (X-Bone, Dynabone). He is a research associate professor in
USC's Departments of Computer Science and Electrical Engineering, where
he runs a summer internship program (SGREP) and advises a number of
graduate students. He has published over 50 papers and is co-author of a
high-speed networks book. Joe is a member of Sigma Xi, IEEE, and ACM. He
co-Chairs the IEEE ITC (Internet) committee, is ACM SIGCOMM’s Conference
Coordinator, and is active in the IETF. He also serves on the editorial
boards of IEEE Network and Computer Networks.
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February 04
Speaker:Luigi Rizzo
Title: Overview of the CoMo system (work in progress) (slides)
Abstract:CoMo (Continuous Monitoring) is a system for capturing Internet traffic at multi-Gbps speeds, and exporting both relevant metrics computed in real time, and the last 24 hours of packet level traces, to a centralized collection system. CoMo would allow network operators to quickly localize and react to undesired network events(e.g., denial of service attacks or router misconfigurations) and, also, to post-process the captured data traffic to further investigate unusual traffic patterns.
In this talk we will focus on the design challenges posed by asystem of this kind (and basically, by most high speed packet processing systems) using off-the-shelf hardware, in particular with respect to the handling of overloads. We will also present design of the CoMo software and the approach we followed to make it easily extensible.
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February 11
Speaker:Soren-Aksel Sorensen
Title: More than brute force: Petaflops in the modern world. (slides tar.gz)
Abstract:The desktop revolution has placed massive processing power at the finger tip of most people. Few people today can complain that they have insufficient access to processing power. Ubiquitous computing is seen as a reasonable challenge and we can now see the outline of a processing society similar to those found in science fiction novels. However, High Performance Computing(HPC) seems to have missed the boat. The traditional time shared batch submission environment still rules.
I will be talking about my vision of HPC and the changes I believe we have to make in order to get to that vision. The challenges are both in the way we build models and in the way we use the available resources. Grid computing can bring us some way towards this goal, but there are many challenges to vistually every branch of computing if we are to succeed.
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February 18 (Reading week)
Speaker:Piers O'Hanlon
Title: Streaming video over multiple simulateous TCP connections. (slides (pdf))
Abstract: We present a brief investigation into streaming a video source across multiple TCP connections to improve throughput through firewalls and NAT boxes.
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February 25
Speaker:Theodore Hong (Imperial College)
Title: Current developments in Freenet
Abstract:Freenet is a peer-to-peer network designed to provide efficient and anonymous information publication. It is one of themost widely used such systems, with over two million downloads. Inthis talk, we give an overview of the state of the Freenet network today and discuss some of the new developments currently being experimented with, notably proposed changes to the routing algorithm and mechanisms for load limiting.
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March 03
Speakers:John McCarthy, Dimitrios Miras and Angela Sasse
Title: Sharp or Smooth? Comparing the effects of quantization vs. frame rate for streamed video slides (ppt)
Abstract:
Using a new methodology to evaluate the perceived video quality, we test the claim that high frame rate is more important than quantization when watching high motion video, such as sports coverage. In two studies we examine the relationship between physical quality and perceived quality metrics. In Study 1, 41 soccer fans viewed CIF-sized images on a desktop computer. Study 2 repeated the experiment with 37 soccer fans, viewing the same content, in QCIF size, on a palmtop device. Contrary to existing guidelines, we found that users prefer high-resolution images to high frame rate. We conclude that the rule "high motion = high framerate" does not apply to small screens. With small screen devices,reducing quantization removes important information about the players and the ball. These findings have important implications for service providers and designers of streamed video applications.
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March 10
Location: Room 214
Speaker:Stephano Street
Title:GDM and JPS systems for distributed computing.
Abstract:
The increasing demand on computational resources has led to much interest in Grid technologies. Among the user areas with such needs is Bioinformatics, which has a seemingly persistent demand for computational cycles. The JPortal & GridDM systems are being designed to help provide a transparent use of resources over multiple domains and application types. The main problems associated with sharing cluster resources over domains is scheduler communication; at the core of the GridDM is a solution to this problem. The JPortal is an application driven single point of entry to the system for registered users; it provides a host of features that help to overcome short falls in the current technologies as discovered in recent research.
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March 17
Location: Room 214
Speaker:Mark Handley
Title: Internet Denial-of-Service Attacks,
slides (pdf)
Abstract: A discussion of the spectrum of possible denial-of-service attacks onInternet systems, lessons learned, and some random musings onarchitectural changes to reduce the threat. The background material is from this paper Internet Denial of Service Considerations
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March 24 (last week of term)
Speaker:Lionel Sacks (EE, UCL)
Title: "What should a network think about its self?" (slides (pdf))
Abstract:
There have been many initiatives in automation of network monument and control, many of which have used AI techniques to some degree. However,these techniques have tended to be embedded in otherwise classical distributed computing architectures. This discussion (ahem) will consider some ideas on how - and why - we might view the overall system as a thinking thing with some empirical and engineering results form our recent work.
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March 31
Speaker:Richard Gold (Computer Science, Uppsala University)
Title: Underlay Networks (slides (pdf))
Abstract:
We see the lack of adjustable indirection as being a key problem with today's Internet. Currently, there is only one way that forwarding, routing and service addressing can occur in an IPv4 network. We wish to reach into the network and make these mechanisms explicit. We propose an underlay network (a network below the network layer) as one way of acheiving these goals.
We imagine that the underlay would have native support for building custom, bespoke networks such as: Peer-to-Peer networks, Content Delivery Networks (CDNs), Proxy networks etc. Our approach is to sit underneath the IP stack (or other network layer). Do not confuse the stack above with temporary structures and state. We can easily build a temporary network on-the-fly which can then be removed when not needed - particularly suitable for ad-hoc routing. We have already built such a system dubbed LUNAR.
Current work is based on building custom network instances (WaveLAN, Ethernet, UDP, PPP etc.) with looking towards how translating between multiple instances in a node can take places. The objective of this is to enables clouds comprising of different network instances can be brought together on an ad-hoc basis.
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April 28(Room 214) (first week of term)
Speaker:Rev Adrian Kennard(Andrews and Arnold Ltd)
Title: Broader Broadband
Abstract:
Making the best use of multiple broadband internet connections to
provide better speed and reliability.
The talk addresses the different requirements for increased speed and
reliability and the way different solutions meet these differing
requirements. It is focused mostly on solutions from products and
services we offer, but provides a good general overview of the issues.
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May 05
Speaker:Prof. Polina Bayvel (UCL)
Title: Optical network design - dynamic vs static wavelength routing?
Abstract: Wavelength-routing is an elegant technique for routing and processing of
information in core networks and the key problems there are in optimising
wavelength assignment and minimising wavelength resources utilised (ie
number of wavelengths) - a kind of graph colouring problem, solvable with
good heuristics where wavelength assignment can be optimised subject to a
given traffic demand. Termed WRONs (wavelength-routed optical networks) -
they are relatively easy to design but may not be efficient since
sub-wavelengths capacities can not be addressed and a possible solution for
this is the dynamic allocation of wavelengths. One approach is optical
burst switching, where electronic packats are aggregated at the network
edge and then assigned to wavelengths either in a hop-by-hop basis or
transparently, with or without acknowledgement of the allocated
resources. Are there any operational benefits with dynamic networks where
resources are allocated on a request basis? Is this dependent on traffic
statistics and/or traffic self-similarity? These questions, together with
some results on the design of optical burst switched networks, will be
addressed. Burst aggregation, dynamic wavelegth routing and request
scheduling will be discussed and it will be shown that traffic
self-similarity has no impact on optical network design.
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May 12
Speaker:Wayne Luk (Imperial College)
Title: Reconfigurable hardware for network applications
Abstract:
The talk describes current research on exploring the use of reconfigurable hardware for network applications. There has been rapid advances in density and capability of reconfigurable hardware such as Field-Programmable Gate Arrays. I shall provide an overview of a method for mapping high-level descriptions, captured in the Ponder language, into packet filters in reconfigurable hardware to produce internet firewalls. Other applications targeting reconfigurable hardware will also be described.
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May 19 (slot taken)
Speaker:Antonio Carzaniga , University of Colorado at Boulder
Title:Content-Based Networking : Design of a Content-Driven Communication Service
Abstract:
Content-based communication is a communication service whereby the flow of messages from senders to receivers is driven by the content of the messages, rather than by explicit addresses assigned by senders and attached to the messages. Using a content-based communication service, receivers declare their interests by means of selection predicates, while senders simply publish messages. The service consists of delivering to any and all receivers each message that matches the selection predicates declared by those receivers. Content-based communication subsumes a service commonly known as publish/subscribe event notification. This talk is about the design of a content-based communication network. I will first introduce the basics of content-based networking, covering the service model and the network architecture. I will then present a routing scheme and aforwarding algorithm that realize the stated service model.
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May 25
Location: Room 214
Time:4 pm
Speaker:Jeremiah Scholl(Media Technology Division,Luleå University of Technology)
Title:An HCI Approach to Scalability in Video Conferencing
Abstract:
The goal of providing desktop video conferencing to larger and larger
groups has received a vast amount of attention from the research
community since the early 90s. In general, the majority of progress has
occurred in two areas, these being video compression, which reduces the
size of each individual stream, and multicast delivery (IP Multicast and
overlay networks), which seeks to efficiently deliver a single stream to
multiple users. Despite a fair amount of progress in both areas, today
it is still relatively difficult to serve groups with a few dozen or
more users.
The seminar will focus on the Human Computer Interaction side of the
problem, and present a few ideas on how well designed user interfaces,
and complimentary bandwidth sharing schemes based on human communication
patterns can be used to help satisfy larger groups, independent of the
codec or delivery system used. In addition, the seminar will introduce
an upcoming study that we will be conducting here at UCL (with the hope
of getting some feedback :)) into heterogeneous bandwidth sharing, with
the goal of showing the benefits that can be provided by providing a
larger share of session bandwidth to a subset of "important" group users.
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May 26
Speaker:Peter Kirstein
Title: Regional Satellite Internet Access for the S. Caucasus and Central Asia The SILK Project - slides (ppt)
Abstract:
The ancient Silk Road was not only a trade route but also an all-important road for the transfer of information and knowledge between major regions of the world. The SILK Project is bringing cost effective, global Internet connectivity to nine former Soviet republics of the Caucasus and Central Asia through state-of-the-art satellite technology, thus creating a virtual Silk information highway. The aim of the SILK Project is to increase significantly the exchange of information with, and between, academic and educational institutions in these regions. It is the first time that a NATO-sponsored initiative is being managed under an EC project with significant support from Cisco and others. The network is now operational in eight countries, and we are considering the next stage of the project.
The talk will describe the background of the project, the network technology, what services are provided, and both the technical and organisational governance. There are some technical novelties like the way bandwidth is shared, caching, some use of Voice/IP and experiments in IPv6. It has had significant impact including video conferences involving several Heads of State. It will also describe a number of related training activities.
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June 02
Speaker:Prof. Fred Piper (Information Security Group, Royal Holloway)
Title: Authentication
Abstract: IIdentifying users is a central problem when using distributed systems. The limitations of using cryptography based solutions and/or the something known plus something known approach have 'always' been acknowledged. We will look at some of the problems with some proposed solutions. We might end, (or even start!), with an open discussion on National ID cards, given sufficient interest. (OHP needed)
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June 09 (last week of term)
Speaker:Iain Phillips (Lecturer, Computer Science, Loughborough University) and Jose Hernandez (PhD student, Computer Science, Loughborough University)
Title: Measuring and Modelling the Internet
Abstract:It is widely recognised that the networks community needs accurate models of the traffic behaviour Internet and other large networks. It is further recognised that such models should be based on measurements of the existing Internet. Researchers at Loughborough have been involved in Network Measurement for over 10 years, both as a research topic and providing measurement applications to BT operations.
In this seminar we present some techniques to characterise Internet delays. The work aims to find a simple mathematical represenation, i.e. distribution parameters, for the end-to-end performance of Internet links. Our current model is based on a weighted combination of Weibull distributions. We will present the model, techniques for discovering the best combination of parameters, some theoretical backing and discuss possible applications.
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Tuesday July 13, 12 noon, room 203
Speaker:Ran Atkinson (UCL CS)
Title: Naming and Addressing in the Internet
Abstract:
This talk provides a quick survey of the existing namespaces
in the Internet today. Then it suggests that there are
problems with the current architecture and very briefly
outlines a prospective approach that would add a new namespace
to the Internet Architecture.
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July 28
Speaker:Ian Wakeman (Department of Informatics,University of Sussex)
Title: "Policy management of pervasive computing services through natural language" with David Weir, Bill Keller, Julie Weeds, Tim Owen and many more (slides) Nathab project page
Abstract:
In this talk I will describe ongoing work in a multi-disciplinary
project to develop a policy management architecture for pervasive
computing. Our main driver is the need to provide a natural language
interface, so that speech can eventually be used as the main input
channel. We are therefore focussing on developing a system which is
designed around the use of natural language to specify how to control
the interaction and use of services.
We have taken a corpus of policies from various people and
used these to drive the design of a policy description logic and an
associated ontology. Simultaneously, we have been working on a novel
service composition architecture, based on events and late binding
dependent on context. The flow of events and action requests is then
controlled by the interpretation of the policy sentences. In this
talk, I will describe the current state of the project, and the
challenges that remain to be met.
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Thursday July 29
Room 214
Speaker:Brian Levine (UMass)
Title:Threats to Privacy from Passive Internet Traffic Monitoring
Abstract:With widespread acceptance of the Internet as a public medium for
communication and information retrieval, there has been rising concern
that the personal privacy of users can be eroded by malicious persons
monitoring the network. A technical solution to maintaining privacy is
to provide anonymity. There have been a number of protocols proposed for
anonymous network communication. We show there exist attacks based on
passive traffic monitoring that degrade the anonymity of all existing
protocols. We use this result to place an upper bound on how long
existing protocols, including Crowds, Onion Routing, Mix-nets, and
DC-Net, can maintain anonymity in the face of the attacks described.
This provides an analytical measure by we can compare the efficacy of
all protocols. Our analytical bounds are supported by tighter results
from simulations, and we made empirical measurements of our assumptions.
We found that mix-based protocols offer the best tradeoff of performance
and security.
In our most recent work, we have looked at further problems with
protecting privacy: attacks to
detect signatures of users and webservers that persist over days or
weeks. VPNs created by ssh tunnels or secure wireless connections (e.g.,
WEP) as implemented are not sufficient to block these signatures, even
though they provide more protection than SSL-based connections that have
been looked at previously for the same problem. We designed an attack
and evaluated it with real Internet measurements: allowed a training
period, we found an attacker could guess which exact web site (in the
training set) was visited by a user through an encrypted link almost 40%
of the time; 70% of the time the correct answer was in the attacker's
top five guesses.
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August 11
Speaker:Venus Shum (UCL, EE)
Title: A cluster-based approach for data handling in self-organising sensor networks. slides (ppt)
Abstract:
With the advances in wireless technology coupled with intelligent devices, distributed and self-organising sensor networks have gained increasing importance for environmental monitoring. In the case of the SECOAS oceanographic monitoring project, a sensor network provides a viable and low cost alternative to the traditional expensive and large sensor packages used in oceanography.
One of the major challenges of SECOAS is the development of an appropriate data handling technique, which is required to preserve significant phenomena within the data for the oceanographers, whilst remaining power efficient. We present a cluster-based approach to the problem of spatial sensing and data fusion. We place emphasis on the creation of clusters of nodes with similar spatial attributes by the use of distributed algorithms mimicking some biological entities, for example quorum sensing. These algorithms are supported by a light-weight operating system, kOS. Additionally, the self-organising behaviours of the clustering algorithm will also be discussed in the presentation.
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September 22
Speaker: Mark Handley/Saleem Bhatti
Title: Plans for HEN (Heterogeneous Experimental Network)
Abstract: HEN is intended to be a shared facility for running networing
experiments. This should remove the need for half of us to have
mini-clusters under our desks - which won't be possible in the new
building. The hope is that it should become much easier to do
experiments without spending ages acquiring hardware, setting up an
OS, ensuring security, etc.
We'll discuss our plans for HEN, what we've done so far, next
steps, and longer term ideas. The reason for discussing this now is to
sanity check that what we think we need is what YOU think we need. So
come along and brainstorm about what you might want from experimental
networking infrastructure, and how you might help out.
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September 29 Nets Group Meeting
Location : G205 in Gower Street (number 66-72, second floor) NOT THE PEARSON BUILDING
Time : 2pm
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October 6
Speaker:Rae Harbird
Title:Adaptive Resource Discovery for Ubiquitous Computing paper (pdf),slides (ppt)
Abstract:
The terms pervasive and ubiquitous computing are used to describe a smart space populated by hundreds of intelligent devices that are embedded in their surroundings. Characteristically, ubiquitous computing devices must blend into the background, unobtrusively collaborating to provide value-added services for users. Services are thus essential to the success of this technology and, as a result, both service discovery and service management will play a vital role in generating the revenue stream that is a prerequisite for sustainable ubiquitous deployment. On the one hand, the services provided should be evident by their richness and variety and on the other, the complexity inherent in the environment must be hidden from users. In this paper, we describe RUBI, a resource discovery framework for ubiquitous computing. RUBI represents anovel approach to resource discovery, because the primacy of the need for adaptive autonomic behaviour is established within its design.
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October 14(THURSDAY)
Room 214
3pm until 5pm
Speaker:Ken Carlberg(Johns Hopkins University / SAIC)
Title: Emergency Communications (slides ppt)
Abstract:
The events of September 11, 2001 have raised the awareness and need to communicate as needed and where possible during emergencies and go beyond television and radio as sole sources of information. This seminar uses several perspectives in covering the topic of emergency communications. Subjects such as the relative importance of certain communication (e.g., who has priority and how is that priviledge granted), examples of existing prioritized emergency communication systems, and a discussion of the Internet in the context of emergencies are presented.
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October 20
Speaker:Ian Brown (UCL, CS)
Title: Who's watching you on the Internet(slides ppt)
Abstract:
The last two decades were a time of momentous change for government
eavesdroppers. The UK communications market shifted from a large
government-owned monopoly provider, to competing large private telcos,
to a fragmented market containing hundreds of firms. The technologies in
use changed from mainly analogue systems through to digital networks
running SS7 and on to IP systems. Finally, the privacy rights in the
European Convention on Human Rights have had an increasingly strong
application through the courts.
These changes have shaken up the previously cosy world of communications
intercepts. Whereas the Post Office (and the 'non-existant' GCHQ) would
quietly wiretap communications on the say-so of senior police and
intelligence officers, a range of new legislation has had to be put in
place to maintain this "intercept capability" for intelligence and law
enforcement agencies given modern networks and human rights legislation.
This seminar will discuss this legislation and the effect it has had on
ISPs' and phone companies' networks as well as the privacy of UK citizens.
Speaker's Bio.:
Ian Brown is an honorary research fellow at UCL, from where
he received a PhD in the field of communications security. He has spoken
and written extensively on communications and healthcare privacy,
copyright and e-voting. Dr Brown is advising the US government on the
security of their next-generation emergency communications systems, and
is the co-author of a recent Kluwer book on this subject. He has
consulted for other large organisations such as the BBC, JP Morgan and
Credit Suisse. Brown is also a trustee of Privacy International and on
the advisory boards of Creative Commons UK and the Foundation for
Information Policy Research. He is a Fellow of the Royal Society of the
Arts and a member of the Royal Institute of International Affairs, the
International Institute for Strategic Studies and the Association for
Computing Machinery.
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October 27 Nets Group Meeting
Location : G205 in Gower Street (number 66-72, second floor) NOT THE PEARSON BUILDING
Time : 2pm
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November 03
Speaker:Bob Briscoe, BT
Title: Shared control of networks based on re-feedback slides (pdf)
Abstract: Accurately characterising paths is the foundation of both resource sharing
and routing in packet networks. Re-feedback is a simple realignment of
metrics so that data headers characterise their downstream, rather than
upstream path. Then the choice between network and end-point control can be
made at run-time rather than prejudged as part of the network architecture.
The approach is to use mechanism design - a branch of game theory.
Incentives are arranged to ensure honesty and responsibility will be the
dominant selfish strategies, even for brief flows, enabling natural
solutions to problems in congestion control & policing, denial of service
and routing.
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November 10 : Room 214
Speaker:Arjuna Sathiaseelan (Kings College, Dept. of Computer Science)
Title:EPDN: Explicit Packet Drop Notification and its uses. slides (ppt)
Abstract:
The Internet is experiencing an exponential growth in users and
network traffic. As the Internet grows larger and larger, the
performance of the network is subjected to severe performance
degrading issues such as congestion in the network, corruption of packets
and reordering of packets. Reordering or Corruption of packets
decreases the TCP performance of a network, mainly because
it leads to overestimation of the congestion of the network. Thus it is
imperative to propose a mechanism that allows the TCP sender to know the
exact cause of the out of order data. We propose a mechanism called the
Explicit Packet Drop Notification (EPDN) that allows the gateway to
inform the TCP sender about dropped packets. We also propose two new extensions
to TCP called the Reorder Notifying TCP (RN-TCP) for wired networks and
Robust TCP (TCP-R) for error prone long delay networks, that use the EPDN
mechanism to improve the performance when packets get reordered or
corrupted in the network.
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November 16 : Room G22
Time : 2pm
Speaker:Ian Brown (Dept. of Computer Science)
Title:The politics of control and the Internet slides (ppt)
Abstract: As the Internet became popular in the mid-Nineties, it was often thought of as a Wild West environment where few laws applied. Censorship would be routed around; privacy would be protected with
unbreakable cryptographic codes; nobody would know if you were a dog.
Ten years on, it is obvious that governments and corporations are very
keen indeed to apply real-world controls to cyberspace. Attempts to
restrict the use of encryption have largely failed, but other methods
of surveillance are being developed and deployed. Patent and copyright
laws have been "updated" for the Internet age and wielded gleefully
against open source software and file sharers. Countries such as Saudi
Arabia and China block their citizens' access to large portions of the
Web.
Can the tension between online freedom and control be resolved, or will
there be an ongoing battle between law enforcement agencies,
intellectual property owners and libertarian programmers?
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November 17
Room 203
2.30pm until 3.30pm
Speaker:Judith Johnson (Thales Group)
Title:Policy Based Management for Naval Networks and High Assurance Environments (slides (pdf))
Abstract:
PBM is the answer! Or is it ? ....
This seminar will introduce the major issues associated with securing and
managing networks in high assurance environments, using naval coalition
networks as an example. Policy based management, a popular and widely
applicable delegation technique, is a potential solution to some of the
management issues associated with dynamic networks (and systems) of the
future, even in high assurance environments. However, there are limitations
and constraints to its use.
The seminar will present the Thales Research & Technology (UK) (TRT)
approach to using PBM in such environments. A number of existing
demonstration systems will be described and an indication will be given of
some ongoing research at TRT.
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November 22 - Monday
Location : Cruciform LT2 (please bring your UCL ID cards)
Time : 3pm to 5pm
Speaker:Christophe Diot, Intel Research UK
Title: ad-hoc google - Haggle
Abstract:The Internet is built around the assumption of contemporaneous end-to-end connectivity. This is at odds with what typically happens in mobile networking, where connectivity is intermittent. We propose *opportunistic networking*, a communication model which reflects the reality faced by the mobile user. We describe the challenges that this approach entails and provide evidence that it is feasible with today's technology. We present Haggle, our user-centric architecture and implementation of opportunistic networking.
A paper about Haggle submitted to HotNets III
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November 24Nets Group Meeting
Location : G205 in Gower Street (number 66-72, second floor) NOT THE PEARSON BUILDING
Time : 2pm
Speaker:Saleem Bhatti
Title: Information about several projects (46paQ, MASTS. EASLEA and UKLight) (slides (pdf))
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November 30DCNDS Seminar
Location : G22
Time : 2pm
Speaker:John Souter, CEO of LINX
Title: Monitoring at LINX (slides (pdf))
Abstract: Explaining the overall network monitoring issues at LINX with a view to what the LINX are aiming for in the future (including some work already in progress).
[Top]
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December 01
Speaker:Yangcheng Huang (UCL CS)
Title: Scalable Signaling Underlay for Overlay Networks (paper (pdf)) (slides (ppt))
Abstract:
This paper presents the design of a scalable decentralized signaling underlay infrastructure, which features with DHT based management information storage and query-based state lookup mechanism. The signaling underlay is aimed to apply a decentralized peer-to-peer style searching and discovering engine into management and control plane of the overlay network, including grid networks and p2p applications, to
facilitate deployment of QoS service.
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December 08
Speaker:Bob Briscoe, BT
Title: Overview of BT's Networks Research Centre (slides (pdf))
Abstract: A romp through BT projects of relevance to the NRG:
- Overall themes:
- Motivation
- The science of computational networking
- Current projects:
- Open Spectrum potential (Collaborative phased arrays, etc)
- Motivation Management in Peer to Peer Services
- Privacy with pervasive computing
- 2020 Communications Architecture - sub-projects on:
- The science of computational networking
- Shared control; shared value
- Routing, naming and addressing
- IP e2e QoS
- Deep packet inspection (applicability)
- BT's 21st Century Network programme
- Some historic projects (watchcast (Global event messaging), M3I (Market
Managed Multiservice Internet), mWare (multicast endpoint middleware),
InternetMart (when we invented Web e-commerce but forgot to patent it)
- Likely future directions
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December 15 (last week of term)
Speaker:Damon Wischik (joint work with Gaurav Raina (Cambridge))
Title:Queueing theory and TCP congestion control
Abstract:
In large multiplexers with many TCP flows, the aggregate traffic flow
behaves predictably; this is a basis for the fluid model of Misra, Gong
and Towsley and for a growing literature on fluid models of
congestion control. In this paper we argue that different fluid
models arise from different buffer-sizing regimes. We consider the large
buffer regime (buffer size is bandwidth-delay product), an intermediate
regime (divide the large buffer size by the square root of the number of
flows), and the small buffer regime (buffer size does not depend on
number of flows). Our arguments use various techniques from queueing
theory.
We study the behaviour of these fluid models (on a single bottleneck link,
for a collection of identical long-lived flows). For what parameter
regimes is the fluid model stable, and when it is unstable what is the
size of oscillations and the impact on goodput? Our analysis is based on
an extension of the Poincar-Linstedt method to delay-differential
equations.
We find that large buffers with drop-tail have much the same performance
as intermediate buffers with either drop-tail or AQM; that large buffers
with RED are better at least for window sizes less than 20 packets; and
that small buffers with either drop-tail or AQM are best over a wide range
of window sizes, though the buffer size must be chosen carefully. This
suggests that buffer sizes should be much much smaller than is currently
recommended.
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