Larry: Practical Network Reconfigurability in the Data Center
summary
Larry reconfigures small groups of racks (typically 2–6 racks) by wiring spare ToR uplinks through a low-cost electrical circuit fabric and a tiny local controller that uses per-port stats. A prototype 40 Gbps electrical circuit switch is built and measures about 18 ns switching; experiments and simulations report tail FCT improvements up to 2.3x and roughly 2× better performance-per-cost versus static oversubscribed designs, while requiring no global control changes and deploying incrementally using spare ToR ports.
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chapters (12)
- 0:00Intro
- 0:25Large-scale data center networking
- 1:06Network flexibility
- 3:28Our solution: local reconfigurability Reconfiguration at a scale of 2 to 6 racks Transparency and incremental deployment
- 4:28First approach: Non-shortest path routing
- 6:01Larry, reconfiguration at the physical layer
- 6:48Larry architecture
- 9:32Control plane Small local soft-state controller
- 10:43Performance evaluation
- 11:40Prototype of rack-scale circuit switch
- 12:2399th percentile flow completion time
- 14:34Performance per
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