Copyright © 2005 John Wiley & Sons, Ltd. Sensor network software update management: a survey By Chih-Chieh Han, Ram Kumar, Roy Shea and Mani Srivastava* ,† Software management is a critical task in the system administration of enterprise-scale networks. Enterprise-scale networks that have traditionally comprised of large clusters of workstations are expanding to include low-power ad hoc wireless sensor networks (WSN). The existing tools for software updates in workstations cannot be used with the severely resource-constrained sensor nodes. In this article, we survey the software update techniques in WSNs. We base our discussion around a conceptual model for the software update tools in WSNs. Three components of this model that we study are the execution environment at the sensor nodes, the software distribution protocol in the network and optimization of transmitted updates. We present the design space of each component and discuss in-depth the trade-offs that need to be considered in making a particular design choice. The discussion is interspersed with references to deployed systems that highlight the design choices. Copyright © 2005 John Wiley & Sons, Ltd. *Correspondence to: M. Srivastava, Department of Electrical Engineering, University of California, 6731-H Boelter Hall, Los Angeles, CA 90095-1594, USA. † E-mail: mbs@ee.ucla.edu Introduction T he recent advances in MEMS, microelec- tronics and the advent of ultra-low-power radio technologies such as Zigbee have made sensing, computation and communication truly pervasive. Wirelessly connected networks of resource-constrained sensor nodes in various forms are gradually making their way into the market and our lives. Technologies such as radio frequency identification (RFID) are already chang- ing the nature of supply-chain management for big retailers. 1 Intelligent sensor networks are increasingly being deployed for safeguarding crit- ical infrastructures. 2 M2M (machine-to-machine) networks are being used by Intel to monitor the health of the expensive fabrication machinery. 3 Despite many potential benefits, the success of sensor network technology hinges upon its ease of use and maintenance. Indeed, sensor networks will never succeed if they require constant man- agement from an entire IT department. The large scale of sensor networks, the limited resources at every node, and the deployment in environments with high access cost, make the task of managing and operating these systems extremely challeng- ing. This paper focuses on the task of software updates in wireless sensor network systems. While software updates to fix bugs and improve features are common in all systems, sensor networks come with the additional challenge of updating devices with limited computational and energy resources. Tools to help update software in traditional systems have been used for a number of years. Enterprise network administrators often need to check for software updates, download them, verify the integrity and finally distribute them to hundreds of nodes in the network. A tool that helps with this task is the Microsoft Systems Management Server (SMS). 4 SMS includes support for planning application deployment, selective targeting of application deployment, security INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT Int. J. Network Mgmt 2005; 15: 283–294 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/nem.574