Abstract. In this paper, we study the incremental deployability of the CoreStateless Fair Queuing (CSFQ) approach to provide fair rate allocations in backbone networks. We define incremental deployability as the ability of the approach to gracefully provide increasingly better quality of service with each additional QoS-aware router deployed in the network. We use the ns2 network simulator for the simulations. We conclude that CSFQ does not exhibit good incremental deployability.