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< Contents ERCIM News No. 57, April 2004

N2NSOFT Network Simulator - Simulation and Optimisation of Large IP Networks

by Dohy Hong and François Baccelli

N2NSOFT is a technology company that branched off from INRIA and now provides services and software solutions for the design and optimisation of internet protocol (IP) network architectures. N2NSOFT has developed software tools allowing one to simulate large and complex IP networks. Today we can simulate up to ten million parallel flows while taking into account the main IP protocol features.

In current IP networks, decentralised protocols (eg adaptive algorithms like TCP) introduce an end-to-end correlation and complex interaction between traffic and network. Consequently, it is no longer sufficient to understand or optimise each network component separately, ie outside the global context of the network. N2NSOFT proposes a new approach that would allow one to develop both a global understanding of a complex network and an optimisation that takes into account the end-to-end interaction of IP traffic. This is based on the fine description of the whole network and traffic configurations, and delivers for each type of subscriber a statistical guarantee of SLA (service level agreements) in the network, and a statistical quality of services for each application (response time for Internet games, voice and video over IP, goodput obtained 90% of time etc).

Our methodology is based on a flow-level simulation developed by the INRIA research group TREC. This approach avoids packet-level event simulation, which does not scale with the size of the network or the number of flows being simulated. Our approach allows one to simulate networks up to ten thousand times larger than can be handled by existing software tools. This offers new possibilities and an end-to-end vision on large networks.

A prototype of a graphical user interface to monitor the network link states: utilization and buffering.
A prototype of a graphical user interface to monitor the network link states: utilization and buffering.

The technical background to this research was presented at the main conference in this domain, INFOCOM 2002 and 2003, by F. Baccelli and D. Hong (Flow Level Simulation of Large IP Networks, Interaction of TCP Flows as Billiards). This technology has been validated by collaborations with major network companies: it has already been used with success for the dimensioning of large xDSL access networks and in the design of dynamic routing algorithms in core networks. N2NSOFT has the exclusivity of the commercial exploitation of this patented methodology.

At present we are developing tools for core and access networks, including various types of scheduling mechanisms in routers and a number of application and traffic profiles (HTTP, P2P, FTP, Video etc). We have also integrated and mixed packet-level algorithms (eg for WiFi integration on mixed wired-wireless networks), and hope to extend our framework to a wide variety of technologies such as FTTH, GPRS, UMTS etc.

We believe a need has arisen to understand and optimise large, complex IP networks, and that this need is not satisfied by existing tools. Currently there is a critical need to optimise access networks. In the future, with the increase of Internet traffic, it may not be optimal to over-provision even the core network. We need to keep pace with the fast evolution of new technologies (UMTS, VDSL, FTTH etc) and new applications (P2P, internet games, Video on Demand etc) and design a network solution that will deliver the best guarantee to customers.

Our approach offers relevant solutions and enables a global large simulation approach, because we take into account the main and detailed features of IP protocols, including feedback mechanism of TCP. In an increasingly competitive environment, we can help our customers to design and offer rational solutions with guaranteed performance.

Our main clients are telecom manufacturers, operators, ISPs, IAPs, companies providing services, and more generally network professionals who need to design, test, understand, predict or optimise IP network architecture. We would like to develop partnerships with companies willing to exploit our tool in specific domains: with telecom manufacturers and operators because we can offer a new tool, or with software and service vendors because we can provide a complementary tool to their current products.


Please contact:
Dohy HONG, N2NSOFT, France