Discharging the Network From Its Flow Control Headaches: Packet Drops and HOL Blocking

Abstract—Congestion control becomes indispensable in highlyutilized consolidated networks running demanding applications. In this paper, proactive congestion management schemes for Clos networks are described and evaluated. The key idea is to move the congestion avoidance burden from the data fabric to a scheduling network, which isolates flows using per-flow request counters. The scheduling network comprises per output arbiters that grant data packets after reserving space for them in the buffer memories in front of fabric outputs. Computer simulations show that this strategy eliminates head-of-line (HOL) blocking and its adversarial effects throughout the fabric, without having to drop packets. In particular, a simplified model describes this result as a synergy between proactive buffer reservations and fine-grained multi-path routing. Two alternative designs are presented. The first one places all arbiters in a central control unit, is simpler, and has superior performance. T...

• Type: Journal
• Year: 2016
• Where: TON
• Authors: Nikolaos Chrysos, Lydia Y. Chen, Christoforos Kachris, Manolis Katevenis
• Keywords: TON 2016