Same domain
See Also
- Optimisation
- Probability in modelling, algorithms, and verification
- Uncertainty
- Interactions, visualisation and virtual reality
- Decision and control systems
- Sensing systems
- Computing systems
- Modelling and simulation
- Software
Complements
Future networks
In the networking field, the main purposes of current researches and developments are to increase capacity in order notably to handle new traffics and new services, to improve quality of service in terms of both performance and reliability and to support the ubiquity of a global and generalised mobility (network mobility and multi-homing).
The number of available access technologies is growing fast (2G, 3G, 3G LTE, 4G, Wi-Fi hotspots, Wi-Max, xDSL, FTTx, cable, or satellite).
A key concept is the generalisation of self-organisation and autonomic networking, as a mean to create new service paradigms with a user-centric approach or to reduce the operational cost of existing services. Peer-to-peer applications and ad-hoc networks are typical examples of self-organisations at the application or network level. Various Digiteo groups are currently working on several of these topics within several collaborations with telecommunication companies and operators.
Mobile networks
One of the major contributions in this area has been OLSR (Optimised Link State Routing Protocol), a table driven proactive protocol with efficient flooding of control messages in the network. OLSR has been developed by some groups of Digiteo. It is now widely used and contributes to the development of ad hoc networks.
The objectives in the next step has been first to enhance the protocol OLSR and ad hoc networks with features such as quality of service (Bandwidth, real time service, multi-metric), multicast, security, etc. , and then to work on the future Internet (super nova) including thing2thing communication, connectivity, auto-configuration and delay tolerant networks.
Network Coding
Network coding is a new communication concept that permits the packet transmission from one or several sources to one or several destinations, departing from the traditional concept of routing. With network coding, nodes in a network require less topology information (such as routing tables) to deliver information, because the packets may be interweaved in several directions at the same time.
The idea is to perform coding inside the network: typically the forwarder nodes will make linear combinations of the data packets they receive. A destination 14 node will be able to decode as soon as it has a sufficient amount of linear combinations of packets. Several teams in Digiteo already work together on network coding through a common industrial contract.
Network Information Theory
Network Theory is devoted to the investigation of theoretical foundations aiming at the exploration of performance limits of wireless networks. These involve thee characterization of the theoretical limits in end-to-end traffic transport capacity of wireless networks, relationships with Shannon capacity and multi-terminal information theory, scaling laws
characterization as well as the potential impact of autonomic behaviour.
Performance evaluation
It remains one of the key issues for future networks design, architecture and management in particular in the domain of flow and congestion control as well as in traffic analysis.
Several Digiteo teams develop new methods (analytical, numerical, approximations or bounds, stochastic network dynamics by algebraic methods) and use them to analyse networks, control algorithms and traffic and to optimise the network design.
Typical problems concern the analysis of the interaction of a large number of TCP connections in networks composed of many routers with various characteristics WFQ, FIFO, priorities, RED or the analysis of flow and congestion control.
All Optical Networks
Optical communication has evolved from high-capacity, point-to-point links toward full optical networking. Wavelength division multiplexing, originally developed to increase the capacity of the installed fibre base, now forms the basis of flexible optical networking for wide area, metropolitan and access networks.
All optical networks remove Optic/Electronic/Optic conversion to design very high speed switches operating from Gigabits to Terabits. But the network control plan has to be redesigned for all types of switching (fast circuit, optical burst switching, optical packet switching), as it is not possible to use electronic memory anymore. Typically the routing of packets or bursts is quite different from nowadays routing protocols, which are all based on store and forward strategies. Access methods also need to be modified to be consistent with routing mechanism.
Digiteo teams explore this issue via collaborative projects with industry at the medium access level or at the application level with the aim to provide a high speed network to interconnect data and computing grids and large visualisation devices.
Algorithmic aspect for cooperation between selfish operators
The strong competition between operators has raised many interesting problems about cooperation of selfish operators and ISP. They must cooperate to provide a full connectivity but one must add some politics to insure cooperation. In particular pricing, billing and routing strategies have to be designed within this trade-off between competition for customers and cooperation to insure quality of service, mobility and connectivity.
This leads to the equilibrium property (Nash) and optimality (Pareto). Game theory, as mentioned in Probability in modelling, algorithms, and verification, is likely to be of major interest on these issues, as well as some optimisation methods mentioned in Optimisation.
Radio
Wireless communication systems use dedicated frequency bands. Terminals are multiband (GSM, UMTS, Wifi, Wimax) and multimode (TDMA, CDMA, FDMA). Next generation terminals will benefit from software radio to dynamically reconfigure radio interfaces at the physical and medium access levels. Teams in Digiteo will address the optimisation problems, the mobility management and the signal and radio measurements methods as well.
All these competences form a unique framework for crossing scientific and technical results, which should favour the development of original and efficient innovations in this area.
