mirror mirror on the ceiling: flexible wireless links for data centers
DESCRIPTION
Mirror Mirror on the Ceiling: Flexible Wireless Links for Data Centers. Presenter: Lu Gong. About Authors. About Authors: Xia Zhou. PhD candidate, UCSB Fields: Networks & Communications, Mathematics, Microbiology. About Authors: Zengbin Zhang. PhD candidate, UCSB - PowerPoint PPT PresentationTRANSCRIPT
Mirror Mirror on the Ceiling:Flexible Wireless Links for Data Centers
Presenter: Lu Gong
About Authors
About Authors: Xia Zhou• PhD candidate, UCSB• Fields:
Networks & Communications, Mathematics, Microbiology
About Authors: Zengbin Zhang• PhD candidate, UCSB• Fields: Wireless Systems and Networking, Mobile
Computing and Distributed Systems
About Authors: Yibo Zhu• PhD candidate, UCSB• Fields: Data Center Networks, Mobile
Networks and Online Social Networks
Problems with any wired network topology
• Any large-scale network consists of multiple stages→ nr of fibers/wires are doubled/tripled
• Distribute fixed amount of fibers to every rack→ fibers are over deployed for the worst case
• Once deployed, very hard to modify
Our goal• Focus on a subset of applications
– that do not require non-blocking all-to-all communication– exclude high-end datacenter computing
• We hope to create a new primitive– high-throughput, beamforming wireless links in the 60GHz band
Existing works
• Signal leakage→ limits the concurrent active links
• Line-of-sight requirement→ limits the effective range of links
Properties of 60GHz band wireless links
• 7GHz spectrum → multi-Gbps bandwidth• High frequency → small interference• Able to use beamforming to enhance link rate
and further suppress interference• 5mm wavelength → any object larger than
2.5mm can block/reflect signal
Beamforming
• A physical layer technique to concentrate transmission energy in a specific direction
Testbed of link blockage
Testbed of radio interference
3D Beamforming
• Components:– Beamforming Radios– Ceiling Reflectors– Electromagnetic Absorbers
• Prevent local reflections and scattering
Testbed of 3D Beamforming
Microbenchmark: Validate Physical Properties
Microbenchmark: Radios per Rack
Microbenchmark: Sensitivity to Hardware
Scheduling: Goal & Challenges
• Goal– Maximize efficiency– Minimize wireless interference
• Challenges– Require accurate interference model (accumulate interference)– Handle short-lived traffic burst → must be online– Account for antenna rotation delay (0.01s~1s)
Scheduling: Design
• Conflict-Degree based Greedy Scheduling– Goal → Minimize job completion time– Graph coloring problem
• Color: 60GHz frequency channels & time slots– Link preemption or not?– Minimize antenna rotation overhead
Evaluation: Addressing Traffic Hotspots
• Does adding 3D beamforming links to existing wired networks significantly increase available bandwidth for hotspots?
• How significant are the benefits of 3D beamforming over 2D beamforming, and where are they most visible?
• Will antenna rotation delay of today’s rotators be a performance bottleneck for 3D beamforming?
Evaluation: Flow Completion Time
Future Work
• Routing• Traffic management• Priority-based scheduler• Wired/wireless co-scheduling
Related Work
• Address traffic congestion– Network architecture design & traffic scheduling– Modeling network traffic characteristics
• 60GHz wireless technology• Optical circuit switching
Thank you for listening