A startup management system and method, particularly adapted for use in computer and other communication networks, is presented. Rate-based flow and congestion control mechanisms have been considered desirable, including to deal with the needs of emerging multimedia applications. Explicit rate control mechanisms achieve low loss because of a smooth flow of data from sources, while adjusting source rates through feedback. However, large feedback delays, presence of higher priority traffic and varying network conditions make it difficult to ensure feasibility (i.e., the aggregate arrival rate is below the bottleneck resource's capacity) while also maintaining very high resource utilization. The invention applies entry and early warning techniques which increase the initial connect rate of newly connecting sources.