Rate Based Feedback: Some Experimental Evaluation with NetFPGA

Transport protocols that use explicit rate feedback are a promising alternative to the algorithms which use implicit, packet loss based feedback. A key issue in the design of rate controlled communication networks is how new flows may be admitted at a fair and high starting rate. In this paper, for the management of new flows we present a modified NetFPGA Rate Control Protocol (RCP) implementation for a recently proposed admission management process at the routers. Using this implementation, we perform an evaluation of the admission of new flows in rate controlled networks. We conduct experimental tests across a range of bandwidth-delay product environments, and also deal with the arrival of a large number of flows. Our work serves to exhibit that the proposed admission management process appears to be an attractive method for dealing with the admission of new flows while maintaining small queues. Additionally, the algorithm allows the routers to maintain a specified target link utilisation. A consequence of such small queues is that buffers, in routers, may be dimensioned to be much smaller than the current, bandwidth-delay product, buffer sizing rule.