Best Effort Differentiated Services: Trade-off Service Differentiation for Elastic Applications

We propose an architecture and several mechanisms for providing “Best Effort Differentiated Services” (BEDS), a set of services similar to Best Effort in that the QoS provided depends on the network conditions, but differentiated in their tradeoff between packet delay and packet loss probability. This proposal starts from the observation that a single Best Effort service does not fit the needs of all types of elastic applications. In our proposal, the “loss-conservative” service has smaller packet loss probability but larger delay than the “delay-conservative” one. The former is suited for file transfer applications, whereas VoIP can significantly benefit from the delay-conservative service. We provide experimental results that confirm our models’ predictions that file and web transfer and interactive voice applications can simultaneously benefit from this service. The experiments were conducted using networks of Nortel routers and switches implementing our proposed mechanisms.