Buffer management for lossless service in network processors

Fair scheduling and buffer management are two typical approaches to providing differentiated service. Fair scheduling algorithms usually need to keep a separate queue and maintain associated state variables for each incoming flow, which make them difficult to operate and scale in high speed networks. On the contrary, buffer management and FIFO scheduling need only a constant amount of state information and processing, and can be efficiently implemented. In this paper, we consider using buffer management to provide lossless service for guaranteed performance flows in network processors. We investigate the buffer size requirement and buffer allocation strategies by starting with the single output network processor and then extending the analytical results to the general multiple output network processor. A universally applicable buffer allocation method for assuring lossless service is obtained, and the correctness of the theoretical results is verified through simulations.