Powersaving with Universal Plug and Play A narration of a Master’s thesis by Martin Olsson and Jakob Klamra

Universal Plug and Play (UPnP) is A cornerstone in power management is an emerging standard for the protocols that computers use to automatic configuration of network communicate with each other. A connected devices. All UPnP protocol is a set of rules of how devices connected to the network communication between two devices should be made. Different protocols are must be fully powered up at all used for different tasks and different times. Using UPnP therefore means kind of communication. One of these increased power consumption. In protocols is Universal Plug and Play this article a design, (UPnP). UPnP is designed for automatic implementation and evaluation of configuration of networks. UPnP will two different solutions to enable automatically make any device that power management in UPnP are connects to the network instantly discussed. accessible to all other devices on that network. UPnP is completely platform As the cost of advanced electronic and media independent which means devices for consumer use continues to that your coffee pot could be able to decrease, the number of network enabled communicate with your computer using devices in a household is increasing. The a power line. increased number of devices also increases the consumption of electricity, However there is a problem with the whether the devices are connected to a current version of UPnP. For the power line or run on batteries. Lawrence protocol to work all devices must be Berkeley National Laboratory estimates fully powered up at all times. This that home IT equipment, such as office means that no device using UPnP can be equipment and closely related allowed to enter power sleep mode. This communications devices, were is due to the fact that a device in power responsible for consuming 280 sleep mode cannot communicate with kWh/year per American household in other devices. This means that when a 2004. The prognosis for 2005 is even device enters power sleep mode it cannot higher. Reducing this consumption will be found by other devices and bring significant economic savings and information about the sleeping device environmental benefits. It will also can be lost. This goes against the whole extend the lifetime of battery driven idea of UPnP where each device should devices. To achieve this we need devices be instantly accessible and ready to use. that are power management enabled. There are various ways to solve the This means that the devices can enter a power management problem in UPnP. state where they consume less energy, a We have chosen to use two solutions, so called sleep mode. In a sleep mode both containing a power management the devices will shut down parts that are proxy. A proxy can handle the not in use, e.g. the screen or the hard communication for a device that has drive. entered power sleep mode. If the sleeping device is required to be fully powered up the proxy can force it to exit since there is no direct communication the power sleep mode. A proxy can be between devices in the network and the implemented as software in standalone invisible proxy. devices dedicated to running proxy tasks, or integrated in other devices in To prove the functionality of our the network. solutions they were both implemented and tested. Both proxies were tested with The two solutions that we have designed various UPnP devices and all software are called the invisible and the could be run on regular PCs. We tested cooperating proxy. They are very similar the software and concluded that it did as they both use a power management solve the power management problem of proxy, however there are some important UPnP. Both proxies allowed devices differences. The invisible proxy is, just connected to the network to enter power as the name suggests, invisible to other sleep mode without breaking any devices in the network. The invisible existing UPnP functionality. proxy does not communicate directly To show how much energy and money with any devices in the network. that can be saved we estimated the Although there is no direct possible benefits of our solutions by communication with the proxy it will 2008 if they would be widely deployed. listen to all traffic on the network. This These estimates were only made for PCs means that the proxy will know how and printers in American households, much time has passed since the last even though there are many other message from a device in the network. devices that would benefit from using Without direct communication the proxy UPnP and our power management has to guess when a device has entered solution. To make accurate estimations power sleep mode and when to start of the power savings in 2008 we had to handling the communication for the estimate the number of PCs and printers sleeping device. in American households by 2008, and how these devices will be used in this The cooperating proxy does not have to near future. Our estimates were based on guess when a device enters power sleep figures from the Energy Analysis mode since the proxy communicates Program at Lawrence Berkley National directly with all devices in the network. Laboratory as represented by Bruce Whenever a device enters power sleep Nordman. Our conclusions were that by mode it will notify the proxy so that the 2008 the stocks of PCs and printers will proxy can start handling the increase significantly and more devices communication. Without guesses the will be network connected. Our solution is more accurate and eliminates estimates of the stocks are presented in the risk of incorrect assumptions. table 1. However, UPnP devices on the market today are not prepared for direct Since UPnP is a relatively new protocol communication with a proxy and it is hard to predict its impact on the therefore each device that communicates market. Therefore we estimated that with the cooperating proxy needs between 10% and 25% of all network additions to its software. These additions connected devices will use UPnP. are not required for the invisible proxy Table 1. Number of devices in American protocol. One example of such an households 2001, 2008 and connected to a application is battery powered, wireless network in 2008 (all figures are in million) security cameras. Today most security Device Devices Devices Network cameras have to use an external power 2001 2008 connected source and be connected to a wired devices network to send its images to the user. If 2008 a camera can enter power sleep mode PC 85.2 134 127.3 when it is not sending images it can save Printer 61.2 118.9 113.3 enough energy to be mobile, battery

powered and using a wireless network. The estimated total amount of energy This opens the possibility for a low cost, and money (counting at 8 cents/ kWh) battery driven camera that never has to that can be saved by 2008 is presented in be recharged. When the battery is empty table 2. the camera is replaced by a new one.

The camera can be activated by a motion Table 2, Savings achieved by using a power sensor or an external wake up management proxy in all UPnP networks mechanism. All cameras can then be 2008 controlled by a single user interface from Savings in Savings in a laptop over the same wireless network TWh/year million or even remotely over the Internet. $/year Low 1.6 128 These cameras might replace the estimation intrusion alarms that many doors and High 4 320 windows are equipped with today. estimation Even though our solutions are proved to These figures show that a considerable solve the power management problem amount of energy and money can be there is still some work left to be done. saved if our power management solution Our software contains several minor for UPnP would be widely deployed. bugs and our solution could be improved for performance issues. There are also We are to our knowledge the first to parts of the design yet to be design and implement a solution to the implemented. These parts were left out power management problem for UPnP. of the implementation due to lack of Our estimates of power savings show time and equipment, but they have no that this work is highly motivated. bigger impact on the results of this Introducing power management to UPnP project. Our solutions can be extended does not only mean environmental and and improved as we have only designed economic benefits. All battery powered and implemented a first version to prove devices that use UPnP will have an its functionality and to show how the extended battery lifetime because they power management problem can be use less power. With this extended solved in UPnP. battery lifetime a lot of devices that before had to be connected to a power More information about the project that line now can be made mobile and run on led to this article can be found at batteries. Extended battery life and http://www.csee.usf.edu/~christen/upnp/. reduced power consumption also allows many new applications to use the UPnP