Performance Contracts in SDN Systems

May 2017

Published in IEEE Softwarization eNewsletter.

Abstract: SDN virtualizes connectivity and access to the underlying bearers. This enables more variety of routes and new ways to share the bearers to meet customer demands at lower cost. However customers will need assurances about the fitness for purpose of the delivered service for their critical applications. This requires new ways to quantify their requirements and to measure the delivered service that go beyond simple notions of bandwidth/capacity.

Downloadable Paper

The paper is available from the IEEE (possibly for a small charge) here.

Challenges of Network Slicing

January 2017

Published in IEEE Softwarization eNewsletter.

Abstract:There are a lot of technology buzzwords about ‘network slicing’, but what do they really mean? In particular, what does a good ‘network slicing’ solution look like? What do we want from it? What capabilities are needed to deliver these requirements?

Downloadable Paper

The paper is available from the IEEE (for a small charge) here.

Smart networks for smart grids and smart cities; New network science: RINA and ∆Q

March 2016

Paper delivered at the 2nd International Workshop on Smart Grid Technology and Data Processing 18 March 2016 in Suzhou, China

Abstract—Smart grids, smart cities and the Internet of Things all require connectivity that is substantially more secure, resilient, predictable, scalable and efficient than packet networks are today. New approaches are required: here we consider the Recursive InterNetwork Architecture (RINA) and the quality attenuation calculus (∆Q).

Downloadable Paper

A PDF of the paper is available here.

A Study of Traffic Management Detection Methods & Tools

August 2015

Ofcom has published research from Predictable Network Solutions Ltd on the technical feasibility of detecting broadband "neutrality violations". We applied a rigorous scientific framework in order to independently evaluate the efficacy of existing traffic management detection (TMD) techniques, and TMD in general.

The specific issues of TMD are just one part of the general issue of analysing interactions between components and players in digital supply chains, which we are uniquely equipped to resolve. As such, this framework can be applied to the quantitative analysis of wider broadband policy issues, enabling better-informed management and policy decisions. Whilst this is the first time this framework has been applied to inform national policy, it has been successfully used for over a decade to solve many large scale practical problems.

Further details

A further discussion of the significance of this report is here.

Downloadable Version

A PDF of the technical report is available here.

Engineering Quality of Experience: A Brief Introduction

November 2012

Connecting the quality of user experience to parameters a network operator can directly measure and control is a challenge, but one that is of fundamental importance to the successful, efficient and ultimately sustainable operation of packet-switched networks. This paper presents a simple, scientific, solution to this problem based on a quality, rather than bandwidth, centred approach. Quality attenuation is a property that can be directly measured end-to-end across a network, and can also be tied to application outcomes. This permits a systematic approach to delivering good QoE called AREA™, connecting: user/application Aspirations; network performance Requirements; traffic Execution; and outcome Assurance.

Downloadable Presentation

A PDF of the technical report is available here.

NetHealthCheck™  Packet Flow Performance Optimisation

July 2012

NetHealthCheck is a service to uncover performance impairments and sub-optimal aspects of the way that a network is configured, managed and structured (recognising that optimality has different meanings for different Network Operators and even for the same Network Operator at different points in the market cycle).

Downloadable Presentation

A PDF of the white paper is available here.

BT Operate Case Study

August 2012

By working with PNSol, BT Operate gained a new quantitative understanding of how end-user QoE is affected in the network and also the factors, beyond overall utilisation, that might put its SLA at risk. This gives flexibility to optimise planning rules to extract economic benefits, such as a 30% increase in the utilisation of key resources. BTO estimates this to be worth £2.3M, a significant saving of operating budget, and a ROI >20.

Downloadable Presentation

A PDF of the case study is available here.

The Properties and Mathematics of Data Transport Quality

February 2009

These are the slides of talk given at Ofcom in February 2009. It is a brief introduction to 'quality' in data networks and its properties. It introduces those properties and discusses their relevance to broadband services.

It concludes with a discussion as to why, for the benefit of all stakeholders, the industry has to move away from single service networks or the ISP (Internet Solvency Problem) will continue unabated.

Downloadable Presentation

A PDF of the presentation is available here.

Emergent Properties of Queuing Mechanisms

November 2005

Delivering multiple assured services requires that there is sufficient control in the QoS mechanisms to deliver on the per-application network quality (delay and loss) requirements over a range of link speeds.

This report is a worked example which takes several applications, each with different network quality and criticality requirement, assessing how the per-hop behaviours available in today's routers can deliver upon the quality requirements. Each per-hop behaviour is evaluated in terms of its effectiveness in delivering the per-application traffic within the appropriate quality constraints.

Downloadable Technical Report

A PDF of the technical report is available here.

Delivering Predictable Quality in Saturated Networks: Technical Report

September 2003

To assure that a network application behaves predictably under all network loads, there is a need to transport its data packets with at least a minimum quality. Although delivering such quality is not usually an issue for a single application instance on a closed network, adding more instances, applications and users soon raises the potential for the demand on the network to substantially outstrip the supply. The implication is that there is always the potential for saturation to occur - a potential which is all too often realized. The attached whitepaper ("Delivering Predictable Quality in Saturated Networks") explicitly considers saturation of the network and its associated consequences.

Downloadable Technical Report

A PDF of the technical report is available here.