Power Management for Universal Plug and Play

1. New device Existing device SSDP:discover SSDP:alive Discover devices, build device cache Notification thread Proxy cache update thread Logical UPnP device Invokes action Control point Start threads Service Service Action acknowledged Figure 1. SSDP message flows for UPnP Sniff packets Check devices in device cache Check proxy cache Process packets If necessary, send SSDP:alive Update proxy cache Proxy Proxy spoofs for printer and wakes-up printer only when its services are needed. If necessary send answer and update all caches SSDP:discover WOL wake-up packet SSDP:alive Figure 4. Implementation of the invisible proxy Control point Sleeping service Figure 2. Message flows for proxy Table 1. Estimated energy savings CHECK PROXY CACHE DISCOVERY (S3) LISTENING (S1) PROXY DEVICE (S2) S01 Connect S12 Threshold time timeout S23 SSDP:discover for device Notebook PC Desktop PC Laser printer SSDP:discover multicast Device in proxy cache SSDP:alive from device S32a S21 SSDP:discover answer Number of devices (millions) 42.5 84.8 11.3 Timeout S22 CHECK PROXY CACHE REQUEST FOR DEVICE (S4) SSDP:alive S11 SSDP from device Power in “on” (W) 22 82 15 Device not in proxy cache S32b Update threshold time Request for device Power in “sleep” (W) 3 6 5 S24 S42 Device not in proxy cache On without proxy (hrs/wk) 56 56 56 Device in proxy cache S41 WOL to device On with proxy (hrs/wk) 19 15 1 Figure 3. FSM for an invisible UPnP proxy 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 • 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 • 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 Ken Christensen Department of Computer Science and Engineering University of South Florida Tampa, Florida, USA Bruce Nordman Energy Analysis Department Lawrence Berkeley National Laboratory Berkeley, California, USA SNCNW 2005 – Halmstad (November 2005)