A study on reservation-based adaptation for QoS in adversarial MANET environments

Existing quality of service (QoS) solutions for mobile ad hoc networks (MANET) typically use bandwidth reservations along a single path to support the delivery of higher priority traffic. To accommodate the dynamic nature of MANETs, this reservation-based approach has been made adaptive in a number of ways in response to the fluctuating availability of network bandwidth. This approach, however, requires the collaboration and co-operation of intermediate nodes, and assumes they are trustworthy and correctly execute routing and QoS operations. This paper uses a simulation study to demonstrate that this single-path adaptation approach to MANET QoS provisioning is no longer sufficient in adversarial environments, and identifies the conditions under which an additional measure, e.g., an adaptive multi-path routing extension, may be necessary to maintain service quality. The study uses the INSIGNIA signalling system as a facilitator of the single-path adaptation approach, and evaluates its effectiveness in the presence of blackhole and grayhole data forwarding attacks and a denial of QoS request attack on QoS signalling. Results are evaluated using the service quality metric defined in this paper. The results show that blackhole attacks, unlike the other two attacks, can prevent single-path adaptation, thus significantly inhibiting the service quality. Additionally, high network loads contribute to lower service quality. Whilst multi-path adaptation may be used as the routing extension, care must be taken to ensure that the network is not saturated as the result of additional packet transmissions.