Network Modeling and Protocols

The Network Modeling and Protocols group focuses on end-to-end engineering issues that arise in current and future networks. It targets the design and evaluation of information technology and network management approaches from a systems perspective. The group engages in research in the design and analysis of systems that are flexible enough to incorporate changes and evolution in use and configuration, while remaining efficient in their utilization of network resources.

Projects focus on the management and movement of data, including availability and reliability engineering, as well as the modeling of various network components and protocols and their relationship to perceived performance of applications relying on the network. As consumer devices force changes in the requirements of the network, it becomes necessary to better understand the overall operation of a total service oriented architecture. The operation of fourth generation networks must be understood not only from the point of view of the air interface but from the perspective of end-to-end application performance.

Applications

In examining network operation from the point of view of application performance, it is necessary to focus on some particular applications, or classes of applications, which are of interest, since it is impossible to consider all. In terms of applications, the focus of the Network Modeling and Protocols (NMP) group coincides with the overall focus of TRLabs and seeks to support effort in other groups such as eHealth, New Media and Home Technologies by focusing on the interaction of applications in these classes with the network.

Home services are of key interest in that much of the driving force behind the information and communications technology business is expected to come from the residential market in the coming years. In recent years, service providers have been investing a great deal in the deployment of flexible infrastructures based on the Internet Protocol to provide services to residences. There is now, and will be for a number of years, a search for new value added services, which can make use of this flexible infrastructure by deploying new services quickly and efficiently.

Home services of interest include video and multimedia services, gaming and also new services not yet defined. Broadcast video is the most widespread application on the network currently, and video on demand is growing. Features such as fast forward, rewind, scene change etc. can be offered over the network in various ways. Content can also be distributed throughout the network in many different ways, with varying effects on the efficiency of utilization of the network. Techniques such as caching and patching of different video streams and content represent a rich area of research. The modeling of the effect of mixing and matching these techniques in various ways could lead to near optimal or at least efficient ways of utilizing the network resources available.

Gaming has already surpassed Hollywood's motion picture industry in total revenues. This hit driven industry will provide opportunities for subscription based services that can be provided over the network. Since performance is a key consideration for avid gamers, this provides an opportunity for service providers to compete by implementing performance enhancing systems such as proxies and middle-boxes to enhance the user experience. This requires an analysis of the performance issues in the network and of the effect and best use of these solutions.

It may be that new services, which are yet to be defined, will become important factors in the utilization of the networks which are being deployed and in the business models of service providers. The NMP group will consider the interaction of these new services with the network. Will there be new paradigms which, like the advent of peer-to-peer for example, will change the magnitude and the pattern of flows within the network in fundamental ways?

The NMP group will also support initiatives in health services. Medical networks for radiology have so far been a key focus of network research within TRLabs related to health, partly because of an ongoing relationship with the radiology sector, and partly because radiology produces vast amounts of data which must be stored and transported. Research into medical networks will continue and will be augmented by research into home health and telematics from a network perspective. Telemedicine is of particular interest in Canada because of the cost of servicing remote communities with health services. Home health services lies at the intersection of home technologies and ehealth and may turn out to be a driving force in the creation of new services to the home especially in light of the current aging of the Canadian demographic.

The nature of person-to-person communications services are also changing in a way that is affecting requirements on the network. Service providers need to remain far enough ahead of these phenomena to take advantage of them when they arise, and to be prepared for any effects on the pattern of utilization and on the requirements for the network which will provide the infrastructure.

Systems

Research within the NMP group focuses on the modeling, design and improvement of systems which enhance the quality of service, efficiency and service integration associated with the applications of interest. We are also interested in systems which arise from new paradigms in computing and communications which need to be understood from the perspective of their impact on and use of the network.

Systems under study which enhance quality of service include those put into place to effect, monitor and guarantee performance such as Multiple Protocol Label Switching (MPLS), differentiated services (DIFFSERV) and connection admission control schemes. We are also interested in application and service-layer intelligence and in their location and function within the network.

Network efficiency is affected by management systems for resources such as storage and bandwidth. There are systems for multi-cast, broadcast and content distribution, which can be used to minimize the impact of various services on the network. These systems are also under study from the NMP group.

The ubiquitous access of “anything, anywhere, anytime” is becoming more and more expected by users as time progresses. Systems which include new protocols for the seamless integration of services which allow mobility, context aware computing and a common look and feel to various devices and environments need to be studied and understood in terms of their interaction with the network and their co-existence with each other. This includes middleware solutions and systems for security and privacy, among others.

Methods and Tools

The NMP group is primarily involved in simulation, analytical and stochastic modeling, and optimization. These approaches make use of various levels of abstraction to represent networks and the behavior of networks, since it is impossible to model every detail of complex networks. Simulation is a common approach which allows relatively complex models to be used in the analysis of network behavior, although some abstraction is always required.

Analytical and stochastic models can be used to evaluate a large number of scenarios or alternative solutions in a reasonable period of time; however they require a significant level of abstraction. Often, simulation models are used subsequently to validate results for a smaller subset of alternatives.

Optimization models are applied to a number of problems such as packet and job scheduling, channel allocation, resource management and network design and planning. In some cases, in addition to mathematical or simulation models, it is necessary to build small test-beds or prototypes to test the functionality and efficiency of new systems or new configurations of existing systems. A minority of research in the NMP group follows this approach.

Achievements

In the last year, five projects have been completed within the Network Modeling and Protocols group, with five M.Sc. students graduating. Two of these projects focused on models for performance analysis of video transport, with one project producing a simulation model and the other an analytical model which can be used to tweak the performance of the relevant protocols.

Two of the projects were device oriented, with one completing a working hardware prototype of a silicon firewall, and the other project developed a network impairment tool in software, using a network processor platform, in order to improve on the flexibility and cost of existing devices.

The fifth completed project developed an optimization model for the sizing and placement of web caches within a regional Internet service provider, together with simulation models for verification of the results.

Research Priorities

We have six ongoing projects in the NMP group. Two of the projects are device oriented, continuing work on developing hardware and firmware prototypes for firewall and adaptive packet filter functionality.

We have a project using infrared transmitting devices to add security to wireless networks by transmitting encryption codes that cannot be recieved by devices outside of a specific room or area.

We are building simulation models for new I/O technologies such as the InfiniBand architecture which can be used to predict the implications of these technologies for distributed applications.

Two ongoing projects focus on the effective use of web services, by considering the routing of SOAP requests and the optimal selection of web servers.

Our priorities in the coming year will increase our focus on applications and on an end-to-end systems perspective of services which we envision will be carried by the IP infrastructures which are currently being deployed by Internet service providers. The focus is on the provisioning of resources and on the nature and location of intelligence within the the network which will allow new services to coexist effectively and efficiently in these new networks. The projects which we have brought forward this year focus on web services, resource management and control, and on the nature of network intelligence.