Differentiated fairness: service model and implementation

Real-time traffic in the Internet is growing and the best-effort model has not been designed for such challenging streams. The DiffServ (DS) architecture, which permits one to aggregate traffic flows into classes with a common forwarding requirement, is a quality of service (QoS) solution for IP networks. But most of the DS models provide classes getting better performance than others, calling for pricing differentiation and possibly admission control. We explore the possibility of providing a simple, robust and pricing-free QoS solution by practising "differentiated fairness": different classes have equivalent performance according to their specific needs. No admission control is required, no absolute guarantee is provided. This "soft" model has been implemented and tested. Experiments shows that the scheduler can balance resource sharing so that "differentiated fairness" is obtained.