Design Issues for providing Minimum Rate Guarantees to the ATMUnspeci ed Bit Rate Service

We describe proposed enhancements to the ATM Unspeciied Bit Rate (UBR) service that guarantee a minimum rate at the frame level to the UBR VCs. These enhancements have been called Guaranteed Frame Rate (GFR). In this paper, we discuss the motivation, design and implementation issues for GFR. We present the design of buuer management and policing mechanisms to implement GFR. We study the eeects of policing, per-VC buuer allocation, and per-VC queuing on providing GFR to TCP/IP traac. We conclude that per-VC scheduling is necessary to provide minimum rate guarantees to TCP traac. We examine the role of frame tagging in the presence of scheduling and buuer management for providing minumum rate guarantees. The use of GFR to support the Internet Controlled Load Service is also discussed.