7th International Conference on Performance Evaluation Methodologies and Tools

December 10–12, 2013 | Torino, Italy

Jim Roberts, IRT-SystemX, France

Be fair to flows: a fair network is attractive and trustworthy and far more than just adequate

The subject of active queue management is again highly topical with the recent creation of a new IETF working group. Regained interest has arisen notably from the observed failings of traditional approaches to congestion control in environments as diverse as the data center interconnect and the home network subject to "bufferbloat". In this context it is opportune to remake the case for implementing per-flow fair queueing as the standard packet scheduling algorithm in router buffers. Though flow fairness as the basis of congestion control was proposed by Nagle as early as 1985 and feasibility was demonstrated at least 15 years ago in Bell Labs work on PacketStar, the networking research community has largely remained focused on designing new TCP versions and AQM algorithms as if the FIFO buffer were an unavoidable technological constraint. We show how per-flow fairness realizes implicit service differentiation and greatly facilitates network engineering with the notion of "fair networks" appearing as a natural parallel to that of "loss networks". Accounting for the stochastic nature of traffic, simple fairness is generally seen to be preferable to weighted fairness or size-based priority scheduling while longest queue drop is likely the only AQM required.

Jim Roberts very recently joined the French research institute IRT-SystemX to work on a project on Cloud computing and network architecture. He was previously with Inria from September 2009 after spending more than thirty years with France Telecom research labs. He received a degree in Mathematics from the University of Surrey in 1970 and a doctorate in computer science in 1987 from the University of Paris VI. His research is centered on the performance evaluation and design of traffic controls for communication networks. In a long career, he has published around 100 papers, chaired several program committees and been associate editor for a number of journals. He gave the Keynote at Infocom 2013. He is a Fellow of the Société des électriciens et électroniciens (SEE) and recipient of the Arne Jensen lifetime achievement award from the International Teletraffic Congress (ITC).