Transcript Slide 1
Power Management for Universal Plug and Play Jakob Klamra and Martin Olsson Department of Communication Systems Lund Institute of Technology Lund, Sweden Introduction: Problem: increased energy use by IT equipment • More devices in households • IT equipment use is 280 kWh/year per US household - Adds up to about $2.24 billion per year Implementation of proxy: Microsoft Windows XP application written in C • Device cache contains all devices in the network • Proxy cache contains all sleeping devices in the network • Threads for listening to traffic and updating the caches - See Figure 4 Ken Christensen Department of Computer Science and Engineering University of South Florida Tampa, Florida, USA Problem: IT equipment is always on, even when idle • “Always on” is required by some protocols - Universal Plug and Play (UPnP) requires this Bruce Nordman Energy Analysis Department Lawrence Berkeley National Laboratory Berkeley, California, USA Problem of induced energy use is addressed • A power management proxy for UPnP in investigated Implementation tested with a variety of UPnP devices • Intel UPnP tools used for developing proxies and services Expected energy savings: Use of UPnP and stocks of devices predicted for 2008 • Predictions for notebooks, desktops, and laser printers • Energy consumption in sleep and on state predicted - See Table 1 (data from B. Nordman and A. Meier, Energy Consumption of Home Information Technology, Lawrence Berkeley National Laboratory, LBNL-53500, July 2004.) Overview of UPnP: UPnP is for automatic device configuration • Network analogy of Microsoft plug-and-play • Has control points and services • Does discovery, eventing, and control New device Existing device SSDP:discover Discover devices, build device cache SSDP:alive Notification thread Proxy cache update thread Start threads Standardized by UPnP Forum • More than 700 vendors including Microsoft, Intel, Nokia Control point UPnP uses Simple Service Discovery Protocol (SSDP) • SSDP is the key issue - See Figure 1 Difficult to predict usage of UPnP in the future • Estimated between 10% to 25% of devices will use UPnP • Estimated savings is $125 to $312 million per year - At $0.08 kW/hr Logical UPnP device Invokes action Action acknowledged Service Service Sniff packets Check devices in device cache Check proxy cache Figure 1. SSDP message flows for UPnP Process packets Update proxy cache Design of proxy: Proxy spoofs for printer and wakes-up printer only when its services are needed. Summary and future work: If necessary send answer and update all caches Proxy UPnP power management proxy • Use a centralized proxy to spoof for sleeping devices • Intercepts packets on behalf of sleeping devices - See Figure 2 If necessary, send SSDP:alive Proxy allows UPnP devices to enter sleep state • Has environmental and economical benefits • Allows fo extended battery lifetime for mobile devices Future work in several areas • Handling multiple proxies in a network • New functionality for mobile devices • Distributed proxying (e.g., a ”Smart NIC”) WOL wake-up packet Figure 4. Implementation of the invisible proxy Centralized proxy allows devices to sleep • Proxy answers for SSDP:discover messages • Proxy wakes-up sleeping device if services are needed Control point Sleeping service UPnP Forum is standarizing a power manegment proxy • Authors (Klamra and Olsson) members of UPnP Forum • Contributions made by authors • Standard is to be finished in summer 2006 Figure 2. Message flows for proxy Two proxy designs considered • Invisible: requires no changes to devices - See Figure 3 • Cooperating: requires new UPnP service in devices LISTENING (S1) S01 Connect SSDP:discover multicast PROXY DEVICE (S2) S12 Threshold time timeout SSDP from device S11 Update threshold time Table 1. Estimated energy savings S23 SSDP:discover for device SSDP:alive from device S21 Timeout CHECK PROXY CACHE DISCOVERY (S3) Notebook PC Device in proxy cache S32a SSDP:discover answer S22 CHECK PROXY CACHE REQUEST FOR DEVICE (S4) SSDP:alive Device not in proxy cache S32b S24 Request for device Device not in proxy cache Device in proxy cache WOL to device S42 S41 Desktop PC Laser printer Number of devices (millions) 42.5 84.8 11.3 Power in “on” (W) Power in “sleep” (W) 22 3 82 6 15 5 On without proxy (hrs/wk) 56 56 56 On with proxy (hrs/wk) 19 15 1 Figure 3. FSM for an invisible UPnP proxy SNCNW 2005 – Halmstad (November 2005)