In future interconnection networks, congestion management is likely to become a critical issue owing to increasing power consumption and cost concerns. As congested packets introduce head-of-line (HoL) blocking to the rest of packets, congestion spreads quickly. The best-known solution to HoL blocking, virtual output queues (VOQs), is not scalable at all or too costly when implemented in large networks. In previous works, we proposed an efficient and cost-effective solution, referred to as destination-based buffer management (DBBM). DBBM groups destinations into different sets, and packets addressed to destinations in the same set are mapped to the same queue. DBBM eliminates most of the HoL blocking (among packets addressed to different sets). It achieves very good results in terms of scalability, throughput, and robustness. However, depending on the distribution of packet destinations, it may introduce an uncertain degree of unfairness among packets mapped on the same queue. In order to overcome this problem, we propose the dynamic DBBM mechanism (DDBBM). DDBBM dynamically eliminates completely the HoL blocking. Performance results show that DDBBM keeps (and in some cases improves) the good results achieved by DBBM in terms of throughput and scalability. Moreover, DDBBM solves the unfairness introduced by DBBM. As an example of applicability, in this paper we show that DDBBM can be applied to InfiniBand with no hardware modification.
['T. Nachiondo', 'Jose Flich', 'J. Duato']
Destination-based HoL blocking elimination