Steven Simpson

Experiments with SuperJANET/SMDS;
Steven Simpson, David Hutchison;
Second Communication Networks Symposium, Manchester, July 1995, pp 145–148;
Internal Report No. MPG-96-20.

Presented by Steven Simpson

A series of measurements of a computer link using the Switched Multimegabit Data Service (SMDS), as provided in the United Kingdom SuperJANET network, are described in this paper.  The computer link is subject to the effects of using several access networks at the peripheries of SuperJANET, making the measurements valid only in the context of the link from one computer to another, rather than describing any attributes of SuperJANET in general.  However, the measurement mechanism is refined several times in an attempt to filter out non-SuperJANET phenomema.

• MPG-96-20-short-A4.ps.gz [47¾ KB/164¼ KB]
  A4 Postscript, GZIP-compressed
  Abridged for appearance at symposium

• MPG-96-20-long-A5b.tar.gz [94 KB/½ MB]
  A5 booklet, double-sided, 2 A4 Postscripts, Unix tape archive, GZIP-compressed
  Complete with diagrams

• MPG-96-20
  On-line as HTML & PNGs
  Complete with diagrams

• MPG-96-20-long.tar.gz [58½ KB/93 KB]
  HTML & PNGs, Unix tape archive, GZIP-compressed
  Complete with diagrams

Transition to High-Speed Networks — SuperJANET Experience;
Kicheon Kim, Steven Simpson, David Hutchison, Andrew Scott;
Twelfth International Conference on Computer Communication, Korea, August 1995, pp ?!–!?;
Internal Report No. MPG-96-21.

Presented by Kicheon Kim

For the time being, trials to establish the Information Superhighway are booming.  In Britain, JANET has provided wide-area computer communication, and has recently been upgraded to SuperJANET, increasing the throughput by a factor of five to 10 Mb/s, with some sites having PDH access at n × 34 Mb/s.  In this paper, the technological changes seen from a user perspective are addressed.  A multimedia communication-based distance learning project on SuperJANET is introduced and the network performance measurements for this project are presented.  These measurements suggest the employment of reservation protocol and packet scheduling.  We also provide a mechanism for on-the-fly playback of continuous media.

• MPG-96-21.ps.gz [52½ KB/½ MB]
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An Architecture for Flexible Group Management Services;
Silvester Namuye, Steven Simpson, David Hutchison;
Third Communication Networks Symposium, Manchester, July 1996, pp 44–47;
Internal Report No. MPG-96-22.

Presented by Silvester Namuye

An architecture for connection management of distributed group applications is presented in this paper.  The architecture is intended to encourage a uniform appearance to all group applications to assist in their collective management, whilst being sufficiently flexible to cope with all likely multicast mechanisms upon which such applications may be based.  The concept of a media channel is introduced as the application-independent instance of a single application, and becomes the basic unit of management in a group user-agent which therefore manages multiple applications.

Group management, multimedia, media channel, session management.

• MPG-96-22.ps.gz [31¼ KB/124 KB]
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Application of Media Channels to Large-Scale Group Communication;
Steven Simpson;
Ph.D. thesis, Lancaster, submitted September 1998, pp –;
Internal Report No. MPG-98-44.

While computer networks have been of low capacity or poor reliability, their use for real-time communications for human interaction was considered infeasible on any large scale, since audio and video data consumes vast amounts of memory and processing capacity.  However, recent and forthcoming enhancements to network quality, along with advanced compression algorithms, falling costs of memory and fast processors, have allowed such applications to develop, as well as protocols to support them.

On top of this, global interconnectivity of local networks has improved, giving scope to expand human communication application to wide areas, and with many participants.  Such group communication applications have various networking Quality of Service (QoS) demands, such as lower bandwidth but high reliability.  The major challenge in multimedia group communication is therefore about developing network services to support group communication with varying QoS, in order to allow groups of people, potentially very widely distributed around the world, to interact through computers of varying abilities, using combinations of media such as video, audio, and shared editing of documents.

The Media Channel (MC) model is an attempt to unify the control and management of applications of different media types.  It provides common group management facilities for all types of application, and allows participation in an application to be expressed simply as contribution (using a source) and/or observation (using a sink).  This further allows a multimedia group application to be built up from several ‘unimedia’ group applications (the ‘channels’) through the use of a user agent which manages and simplifies a user's participation in several applications.  Participation in multimedia group applications (or ‘sessions’) can then be configured automatically for several users by describing the channels of the session to each involved user agent.  This description itself can be supplied through a channel, with the agents acting as sinks.  The user can control participation in all the channels of the session by (de)activating the agent's session sink, and while joined, session administrators can inform all session participants of new channels to which they are invited.

The MC model's main shortfall is its use of a central manager — an architecture which does not scale well to many participants, and which may lead to uneven management for widely distributed participants, particularly as group populations migrate.  This thesis considers the issues of multimedia group communication, and attempts to realise the MC model.  Some earlier definitions of the MC model are refined in the present thesis, and alternative architectures are designed, implemented and evaluated.  These new architectures allow the management components of a media channel to be placed near to the participants, and then to migrate as participants leave the components' areas, and as new ones join in others.  At the same time, management information to evaluate policies is compressed and distributed among components.  The model is also extended to allow sources to describe their data arbitrarily, enabling sinks to accept or reject them individually depending on availability of local resources.

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Modelling and Improving Flow Establishment in RSVP;
Laurent Mathy, David Hutchison, Steven Simpson;
Proc. of Protocols for High Speed Networks (PfHSN'99) Salem, MA, USA. August 25-27, 1999.  J. Sterbenz and J. Touch (Editors).  Kluwer Science Publishers., pp 133–150;
Internal Report No. mpg-code.

RSVP has developed as a key component for the evolving Internet, and in particular for the Integrated Services Architecture.  Therefore, RSVP performance is crucially important; yet this has been little studied up till now.  In this paper, we target one of the most important aspects of RSVP: its ability to establish flows.  We first identify the factors influencing the performance of the protocol by modelling the establishment mechanism.  Then, we propose a Fast Establishment Mechanism (FEM) aimed at speeding up the set-up procedure in RSVP.  We analyse FEM by means of simulation, and show that it offers improvements to the performance of RSVP over a range of likely circumstances.

• pfhsn99.ps.gz [88 KB/¼ MB]
  A4 Postscript, GZIP-compressed
  

REDO RSVP: Efficient Signalling for Multimedia in the Internet;
Laurent Mathy, David Hutchison, Stephan Schmid, Steven Simpson;
IDMS'99, pp ?!–!?;
Internal Report No. mpg-code.

Presented by Laurent Mathy at IDMS'99

Alarming reports of performance and scalability problems associated with per-flow reservations, have led many to lose belief in RSVP and the Integrated Services Architecture that relies on it.  Because we are convinced of the need for some form of resource reservation, to support multimedia communications in the Internet, we have set about trying to improve RSVP.  By careful study of the protocol, we have identified areas for improvement, and propose REDO RSVP, a reduced overhead version that includes a fast establishment mechanism (FEM).  In this paper we describe the rationale for REDO RSVP and present a detailed analysis of its features and operations.  We also analyse REDO RSVP by means of simulations, and show that it offers improvements to the performance of RSVP.

• idms99.ps.gz [120¾ KB/¼ MB]
  A4 Postscript, GZIP-compressed
  

Provision of Signalling for Programmable Services;
Mark Banfield, Steven Simpson, David Hutchison;
In proceedings of Sixth International Conference on Intelligence in Networks (SmartNet 2000), 20^th–22^nd September 2000, Vienna, Austria, pp 307–330;
Internal Report No. MPG-00-21.

Presented by Mark Banfield at SmartNet 2000

Additional network complexity driven by the demand for new broadband services increases the need for network control and management signalling.  This paper takes stock of this trend and suggests an approach within the context of IEEE P.1520 to separate signalling and associated broadband intelligent services from multimedia data transport so that each may be developed to their full potential.  The authors draw on their experience of development of two signalling systems, one a TINA NRA inspired Connection Management System, and the second based on the P.1520.3 Programmability Architecture, in proposing a new Signalling Transport Service Provider rôle.

• SmartNet_LancUni.pdf.gz [¾ MB/2 MB]
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Component Selection for Heterogeneous Active Networking;
Steven Simpson, Mark Banfield, Paul Smith, David Hutchison;
In proceedings of Third International Working Conference on Active Networking (IWAN 2001), 30^th September–2^nd October 2001, Philadelphia, USA; LNCS 2207, pp 84–100;
Internal Report No. MPG-01-08.

Presented by Steven Simpson at IWAN'01

Active Networking (AN) involves the processing of programs in heterogeneous networking environments.  There are several AN solutions, exposing different APIs and using different languages, and each may be appropriate for different tasks such as high-speed multimedia processing or low-speed routing adjustments.

We describe our active node system, LANode, that separates control- and data-plane activities, and introduce Component Compatibility Markup Language (CCML), a critical component of LANode that allows it to be applied to heterogeneous platforms.

• MPG-01-08.ps.gz [211¾ KB/½ MB]
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Scalable Adaptive Hierarchical Clustering;
Laurent Mathy, Roberto Canonico, Steven Simpson, David Hutchison;
In IEEE Communications Letters, Vol. 6, Nº 3, March 2002, pp 117–119;
Internal Report No. mpg-code.

We propose a new application-level clustering algorithm capable of building an overlay spanning tree among participants of large multicast sessions, without any specific help from the network routers.  The algorithm and associated protocols are shown to exhibit scalable properties.

Clusters, hierarchy, IP, multicast, network

Peer-to-Peer Networking for Programmable Service Deployment;
Paul Smith, Steven Simpson, David Hutchison;
In Proceedings of Practical Programmable Networks: Making Inroads into the Internet (IEEE OpenArch 2002), Short Paper Session, 28th–29th June 2002, pp 41–46;
Internal Report No. mpg-code.

Abstract

Keywords

Peer-to-Peer Networking for Discovering Programmable Resources;
Paul Smith, Steven Simpson, David Hutchison;
In Proceedings of Fourth International Workshop on Networked Group Communications (NGC 2002), 23rd–25th October 2002, pp 141–141;
Internal Report No. mpg-code.

Abstract

Keywords

A performance study of RSVP with Proposed extensions;
Laurent Mathy, David Hutchison, Stefan Schmid, Steven Simpson;
In Computer Communications Volume 25, Issue 18, 1 December 2002, pp 1782–1798;
Internal Report No. ??.

Resource ReSerVation Protocol (RSVP) was developed as an intended key component for the evolving Internet, and in particular for the Integrated Services architecture.  Therefore, RSVP performance is crucially important; yet this has been little studied up till now.  In this paper, we target two of the most important aspects of RSVP: its ability to establish flows and its steady-state overhead.  We first identify the factors influencing the performance of the protocol by modelling the establishment mechanism.  Then, we propose the principles of a Fast Establishment Mechanism (FEM) aimed at speeding up the set-up procedure in RSVP.  We analyse FEM by means of simulation, and show that it offers improvements to the performance of RSVP over a range of likely circumstances.  We also present the principles of a simple mechanism aimed at reducing the steady-state (i.e. refresh) message overhead of RSVP.

Resource ReSerVation Protocol; Internet; Traffic

• Web site with summary, full text and PDF
  HTML
  

Programmable Resource Discovery using Peer-to-Peer Networks;
Paul Smith, Steven Simpson, David Hutchison;
In Proceedings of Fourth Annual International Working Conference on Active Networks (IWAN 2002), 4th–6th December 2002, pp ?–?;
Internal Report No. mpg-code.

Abstract

Keywords