Post on 18-Jan-2016
Network Power Management FundamentalsBob Combs
Lead Program ManagerMicrosoft Corporation
Narsi NagampalliSoftware Development LeadMicrosoft Corporation
Agenda
PC power usageVista power managementGoals for Windows 7 power managementFeature enhancementsDemo Wake-on-LAN in Windows 7Configuration and administrationLogo requirements
Energy Awareness for PCs
Energy costs are rising
PC energy consumption has doubled since 2000
EPA estimates PCs use ~2% of all electricity consumed
Businesses trimming costs
Home users are thinking “green”
PC on 24/7 is 8% of household power usage
From http://www.energystar.gov/ia/partners/prod_development/revisions/downloads/computer/TierII_Network_Issue_Slides.pdf
Hours/year
Off
Sle
ep
100 -
0 -
50 -
Pow
er
(watt
s)
0 8760
Idle
Activ
e
Sleeping PC Equals Real Savings
PC sleeping 14 hours per day saves 598–760 kWh per yearApproximately $63,500 per year for 1,000 PCs
Saves 420-534 kg of CO2 from energy production (~1/10 of average auto)
Wake-on-LAN in Vista
Wake-on-LAN (WoL) off by defaultWake patterns
Magic packetDirected layer2 packetNetBIOS name query packet IPv4 Address Resolution Protocol (ARP) request packetIPv6 Neighbor Solicitation (NS) packet
Vista WoL Observations
Wake patterns don’t account for different network environmentsSpurious traffic in enterprise environment can continually wake machines
Directed packetsSwitches refreshing their tablesNot an issue in home networks
Windows 7 Power Goals
PC should sleep when idlePreserve remote availabilityReduce energy consumption at runtime
Power down devices when not in use
Target Scenarios
Media PCsRemote Desktop/Terminal ServicesFile sharingPrinter sharingEnterprise maintenanceDistributed applications
Network WoL Features in Windows 7
Wake-on-LAN/Wake-on-Wireless LAN (WoL/WoWLAN)
On by defaultRevised set of wake patterns
Power management offloadsAddress Resolution Protocol (ARP) for IPv4Neighbor Solicitation (NS) for IPv6
Device low power on media disconnect
Wake Patterns
Bitmap patternsMagic packetIPv4 TCP SYN packet typeIPv6 TCP SYN packet type802.1x EAPOL request identity message (wireless) packet type
Network Presence Offloads When the System is Asleep
ARP request processing in the NICResponds to IPv4 address resolution requests with the host MAC addressNo ARP caching/management
NS processing in the NICResponds to IPv6 Neighbor Solicitation requests with the host MAC addressSupports public, link-local, and temporary IPv6 addresses
Wake Patterns According to Network Environment
Determined by location: Home vs. workMagic Packet is a common wake pattern TCP SYN IPv4/IPv6 indicates new connection requests; e.g., file sharing Wake for name resolution requests
NetBIOS – IPv4 only LLMNR – environments without DNS
ARP, NS – if no offloads available
Wake on LAN with Network Presence Offload
demo
Low Power on Media Disconnect
While PC is in system working state (S0)On LAN cable disconnect, the NIC is placed in device sleep (D3)On LAN cable reconnect, the NIC into working state (D0)If the system goes to sleep while the cable is disconnected, this feature is canceled
Keywords Added for Windows 7
Finer control of capabilitiesUser can access from Device PropertiesProgrammatic change using WMIKeyword Description
*WakeOnPattern Enable waking on pattern matches
*WakeOnMagicPacket Enable wake on Magic Packet *DeviceSleepOnDisconnect
Enable sleep when media (LAN cable) is disconnected
*PMARPOffload Enable the ARP offload during sleep
*PMNSOffload Enable the NS offload during sleep
*PMWiFiRekeyOffload Enable the WiFi rekeying offload during wireless adapter sleep
Configuration and Administration
WMI interfaces to query and set configuration settings
Configuration of systems
Global administration
Management applications
WMI interfaces to query current and hardware capabilities
3rd party applications
Diagnostics
Network Logo Requirements
WoL logoMust support at least 6 WoL patterns By 2010, must support at least 8 WoL patterns
Network presence offloadsSupport ARP and NS optionallyARP and NS offloads required by 2010
Call To Action
Update hardware and drivers to NDIS 6.20 to take advantage of new Windows 7 functionalityProvide support for at least 8 wake patternsImplement ARP and NS power management offloads on NICSupport new packet type patternsSupport low power on media disconnect
Additional Resources
Windows 7 WDK available with Beta
Released DDI is available on MSDN:http://msdn.microsoft.com
Device driver questionsNDIS 6 Feedback alias: ndis6fb@microsoft.com
Windows Logo Program Web site:http://www.microsoft.com/whdc/winlogo/default.mspx
Related SessionsCOR-T525 Network Device Overview
COR-T540 Windows 7 Power Management Overview
ENT-T551 Windows Server Power Management Overview
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