Virtual Queueing Techniques for UBR+ Service in ATM with Fair Access and Minimum Bandwidth Guarantee

AbstTactThe ATM Forum is currently discussing the need for a new best-effort service called UBR+, which ie, an enhancement to the existing UBR service, to supporit data traffic. The objective of the UBR+ service is to provide each user with a minimum service rate guarantee and a fair access to any excess available bandwidth. In this paper, we present a new efficient scheme for supporting this service. The key advantage of our scheme is that it employs only FIFO queueing (instead of per-VC queueing) and admits simple implementation in ATM switches. Our ideas involve a simple scheduling mechanism that is based on per-VC queueing and incorporate the virtual queueing technique [lo], [ll] that can efficiently emulate per-VC queuing on a shared FIFO queue. Simulation results are presented to show that our schemtas can deliver almost ideal performance for supporting the new service requirements of UBR+.