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Energy Aware Network Operations. Authors: Priya Mahadevan , Puneet Sharma, Sujata Banerjee , Parthasarathy Ranganathan HP Labs IEEE Global Internet Symposium (April 2009 ) Speaker: Sookhyun Yang. Introduction.
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Energy Aware Network Operations Authors: PriyaMahadevan, Puneet Sharma, SujataBanerjee, ParthasarathyRanganathan HP Labs IEEE Global Internet Symposium (April 2009) Speaker: Sookhyun Yang
Introduction • This paper analyzes three energy-saving schemes to configure a switch in a data center network with link redundancy. [Data center network topology]
Energy Saving in a Switch port • Linear power model • Power consumed by each switch depends on • Number of active ports • Line capacity of a port • How can we control a switch for saving energy? • Disable a switch port • Dynamically adapt a port’s link capacity based on its load • Turn off a line-card that have no active ports • Power off a switch that is not being used Line-card [A switch with line-cards]
Three Energy Saving Schemes • Centralized approach • LSA (Link State Adaptation) • Adapts a port’s link capacity (disabled, 10Mbps, 100Mbps, and 1Gbps) according to link utilization. • NTC (Network Traffic Consolidation) • Consolidates traffic into fewer links (and switches). • Disables unused links (and switches). • SLC (Server Load Consolidation) • Migrates jobs for minimizing the number of servers being used. • Applies NTC schemes. [Data center network topology]
Variations of the Three Schemes • SL (Service Level) Awareness • Adds a constraint to ensure that a link’s utilization never exceeds a certain threshold. • Ensures that at least one redundant link exists. • SL awareness policy is combined with each of the three schemes.
Simulation Set-up: Workload • Simulation based on workload of observed traffic • 292 web-servers for 5days in April 2008 • System configuration of 292 web-severs • Quad-core processors, two 1Gbps network cards • Different RAM sizes: 193 servers have 4 GB RAM, 69 servers have 8GB RAM, and 30 servers have 16GB RAM. • Observed results • Workload is memory-sensitive • 130 servers use 90% or greater amount of memory, 64 servers use less than 40%. • Both network bandwidth and CPU of all servers are utilized at most 10%.
Simulation Set-up: Network Topology 2 tier-2 switch (6 line card per switch, 24 ports per line card) 26 rack switches (48 ports per switch) 292 web servers [Data center network topology]
Simulation: How to Compute Power Consumption • Perfect knowledge of an oracle • Link utilization • Job’s traffic specification • Network topology • Power consumption Line-card with no active ports Line speed
LSA (Link State Adaptation) • Link characteristics from 5-day measurement • 90% of links (light traffic) can be set 10 or 100Mbps. • Less than 5% of links (heavy traffic) need to be set 1Gbps. • LSA’s distribution of link speeds between rack and tier-2 switches
Simulation Results NTC (Network traffic consolidation) SLC (Server load consolidation) LSA (Link state adaptation)
Deployment Issues • Track traffic workload • Adapt link capacity based on link utilization statistics • Predict incoming/outgoing traffic • Transition time for adapting link-speeds is between 1-3 seconds, which can affect network performance. • Buffer or ensure the existence of back-up paths
Q&A Thank you!