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

© 2008 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.

The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after

the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.