Towards simple, high-performance schedulers for high-aggregate bandwidth switches

Proceedings - IEEE INFOCOM - Tập 3 - Trang 1160-1169 vol.3
P. Giaccone1, B. Prabhakar2, D. Shah3
1Department of EE, University of Stanford, USA
2Departments. of EE and CS, University of Stanford, USA
3Department of CS, University of Stanford, USA

Tóm tắt

High-aggregate bandwidth switches are those whose port count multiplied by the operating line rate is very high; for example, a 30 port switch operating at 40 Gbps or a 1000 port switch operating at 1 Gbps. Designing high-performance schedulers for such switches is challenging for the following reasons: (i) high performance requires finding good matchings; (ii) good matchings take time to find; (iii) in high-aggregate bandwidth switches there is either too little time (due to high line rates) or there is too much work to do (due to a high port count). We exploit the following features of the switching problem to devise simple-to-implement, high-performance schedulers: (a) the state of the switch (carried in the lengths of its queues) changes slowly with time, implying that heavy matchings will likely stay heavy over a period of time; (b) observing arriving packets conveys useful information about the state of the switch. These features are exploited using hardware parallelism and randomization to yield three scheduling algorithms for IQ (input-queued) switches - APSARA, LAURA and SERENA. These algorithms are shown to achieve 100% throughput and simulations show that their delay performance is quite competitive with respect to the maximum weight matching. The stability proof involves a derandomization procedure and uses methods which may have wider applicability.

Từ khóa

#Bandwidth #Switches #Packet switching #Scheduling algorithm #Bipartite graph #Fabrics #Throughput #Delay #Traffic control #Aggregates

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