1. Power Management for Universal Plug and Play Jakob Klamra and Martin Olsson Department of Communication Systems Lund Institute of Technology Lund, Sweden Bruce Nordman Energy Analysis Department Lawrence Berkeley National Laboratory Berkeley, California, USA Ken Christensen Department of Computer Science and Engineering University of South Florida Tampa, Florida, USA 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 Problem: IT equipment is always on, even when idle “Always on” is required by some protocols - Universal Plug and Play (UPnP) requires this Problem of induced energy use is addressed A power management proxy for UPnP in investigated 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 Standardized by UPnP Forum More than 700 vendors including Microsoft, Intel, Nokia UPnP uses Simple Service Discovery Protocol (SSDP) SSDP is the key issue - See Figure 1 Design of proxy: UPnP power management proxy Use a centralized proxy to spoof for sleeping devices Intercepts packets on behalf of sleeping devices - See Figure 2 Centralized proxy allows devices to sleep Proxy answers for SSDP:discover messages Proxy wakes-up sleeping device if services are needed Two proxy designs considered Invisible: requires no changes to devices - See Figure 3 Cooperating: requires new UPnP service in devices SSDP:discover SSDP:alive Control point Service Logical UPnP device Invokes action Action acknowledged New deviceExisting device Figure 1. SSDP message flows for UPnP Figure 4. Implementation of the invisible proxy Discover devices, build device cache Start threads Sniff packets Process packets If necessary send answer and update all caches Update proxy cache Check proxy cache Check devices in device cache If necessary, send SSDP:alive Proxy cache update thread Notification thread 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 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.) 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 Summary and future work: 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”) 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 SNCNW 2005 – Halmstad (November 2005) Notebook PCDesktop PCLaser printer Number of devices (millions) Power in “on” (W) Power in “sleep” (W) On without proxy (hrs/wk) On with proxy (hrs/wk) 42.5 22 3 56 19 84.8 82 6 56 15 11.3 15 5 56 1 Table 1. Estimated energy savings LISTENING (S1) PROXY DEVICE (S2) Threshold time timeout SSDP:alive Timeout SSDP:alive from device Connect SSDP:discover multicast CHECK PROXY CACHE DISCOVERY (S3) SSDP:discover for device Device in proxy cache SSDP:discover answer Device not in proxy cache CHECK PROXY CACHE REQUEST FOR DEVICE (S4) Request for device Device not in proxy cache Device in proxy cache WOL to device SSDP from device Update threshold time S12 S21 S22 S23 S32a S32b S24 S42 S41 S11 S01 Figure 3. FSM for an invisible UPnP proxy SSDP:discover SSDP:alive Proxy WOL wake-up packet Proxy spoofs for printer and wakes-up printer only when its services are needed. Figure 2. Message flows for proxy Control point Sleeping service