Survivability in Wireless Sensor Networks

Summary form only given. In this paper we survey the issues and concerns surrounding the deployment and maintenance of wireless sensor networks. Research focuses on several distinct areas affecting survivability: 1) power, 2) network/node destruction and repair, and 3) network security. Areas of concern are identified and currently proposed solutions are reviewed. Areas of research targeted at addressing survivability are identified. Wireless sensor networks (WSNs) have a wide variety of potential applications in agricultural, environmental monitoring, homeland security, safety, medical, and military applications, to name a few. The reliance on these WSNs often causes their presence to be mission critical. For this reason, it is vital that these sensor networks remain viable. This paper focuses on the different types of risks inherit in the environment that may cause either a sensor node or entire WSN to fail and the current approaches suggested for addressing these risks. In addition, this paper examines the survivability of nodes and data from a network viewpoint where the nodes are not physically affected but may be attacked by various means of denial-of-service, compromise, or some related detrimental effect. The definition that has been proposed for network survivability is, "the ability of a network to accomplish its purpose, in a timely manner, in light of threats, attacks, or failures". As one can see from the definition, the emphasis focuses on the continued functioning of the network regardless of the type of threat. For traditional computer networks, security and physical redundancy are employed in an effort to assure survivability. Weaknesses have been identified, particularly in the last-mile of a network where damage to the physical network prevents its continued availability. Options, like the use of wireless line-of-site connectivity, are often employed to provide redundancy and thereby, aid in making the network survivable. Wireless sensor networks,- - because of their potential for physical isolation, may be more vulnerable to attack. In addition, due to their characteristic low processor capability, WSNs do not have the capacity to utilize sophisticated anti-intrusion prevention technologies. Creating ways to detect and prevent threats do not, in themselves, help to determine whether a network will be able to operate during an attack. Mobile wireless networks present problems to survivability because of user mobility and free access. Mobile networks are also at risk during software upgrades. Network management tools that operate and maintain modern systems can be plagued with problems, creating an additional point for failure. Two distinct categories of survivability are: 1) information access and 2) end-to-end communication. These requirements apply to all of the networking layers. Building upon these two requirement categories, we examine the cause of WSN failure, both hardware and software based, and then identify means by which survivability may be supported