*2.7.2. Importance*

Trust aware routing in WSN is important for both securing obtained information as well as protecting the network performance from degradation and network resources from unreasonable consumption.

Most WSN applications carry and deliver very critical and secret information like in military and health applications. A WSN network infected by misbehaving nodes can misroute packets to wrong destinations leading to misinformation or do not forward packets to their destination leading to loss of information. Such critical application can be very sensitive to these attacks. Having a trust aware routing protocol can protect data exchange, secure information delivery and maintain and protect the value of the communicated information.

Node misbehavior can cause performance degradation as well. For example, non forwarding attacks decrease the system throughput since packets will be retransmitted many times and they are not delivered. Denial of service attacks can increase the packet delay since some nodes acting as routers will be busy in responding to the attack and enforced to delay the processing of other packets. An infected WSN network can be partitioned into different parts that cannot communicate among each other due to non forwarding attacks. This leads to the demand of increasing the number of sensors or changing the node deployment to return network connectivity. This is very expensive, however, can be avoided if a good secure routing solution is adopted.

Network resources are also affected by misbehaving nodes. For example, Denial of service attacks affect resource availability, whether we consider an offended node as a resource for routing or we consider the availability of data itself. Also, this attack forces offended nodes to consume unnecessary energy on packet reception and processing.

As we can see, the information value and the network performance are directly affected by the security level provided by trust awareness of the routing operation in WSN.
