Initial work in ad hoc routing has considered only the problem of providing efficient mechanisms for finding paths in very dynamic networks, without considering security. Because of this, there are a number of attacks that can be used to manipulate the routing in an ad hoc network. In this paper, we describe these threats, specifically showing their effects on ad hoc on-demand distance vector and dynamic source routing. Our protocol, named authenticated routing for ad hoc networks (ARAN), uses public-key cryptographic mechanisms to defeat all identified attacks. We detail how ARAN can secure routing in environments where nodes are authorized to participate but untrusted to cooperate, as well as environments where participants do not need to be authorized to participate. Through both simulation and experimentation with our publicly available implementation, we characterize and evaluate ARAN and show that it is able to effectively and efficiently discover secure routes within an ad hoc network.

Existing solutions for QoS-aware routing in mobile multihop networks attempt to discover a QoS-satisfactory route for the user at the user's current location. If a suitable route is not available at the current location, the user is denied access. This approach does not take advantage of the special characteristics of mobile multihop networks. That is, users in these networks are mobile and their connectivity is dependent on their location and the locations of other users. By changing their location, users can alter their connectivity characteristics and potentially obtain better service from the network. In this paper, we propose enhancing QoS-aware routing protocols to take advantage of this characteristic. With our solution, if a satisfactory route is not available at the user's current location, the protocol discovers a nearby location where a better route is available. The user can then choose to move to the suggested location to improve the received quality of service. We demonstrate our idea by appropriately extending a QoS-sensitive version of the AODV routing protocol, and presenting a simulation-based evaluation. Simulation results show the effectiveness and efficiency of our idea.

Admission control of flows is essential for providing quality of service in multihop wireless networks. In order to make an admission decision for a new flow, the expected bandwidth consumption of the flow must be correctly determined. Due to the shared nature of the wireless medium, nodes along a multihop path contend among themselves for access to the medium. This leads to intra-flow contention; contention between packets of the same flow being forwarded at different hops along a multihop path, causing the actual bandwidth consumption of the flow to become a multiple of its single hop bandwidth requirement. Determining the amount of intra-flow contention is non-trivial since interfering nodes may not be able to communicate directly if they are outside each other's transmission range. In this paper we propose two methods to determine the extent of intra-flow contention along multihop paths. The highlight of the proposed solutions is that carrier-sensing data is used to deduce information about carrier-sensing neighbors, and no high power transmissions are necessary. Analytical and simulation results show that our methods estimate intra-flow contention with low error, while significantly reducing overhead, energy consumption and latency as compared to previous approaches.

Most recent ad hoc network research has focused on providing routing services without considering security. We detail security threats against ad hoc routing protocols, specifically examining AODV and DSR. In light of these threats, we identify three different environments with distinct security requirements. We propose a solution to one, the managed-open scenario where no network infrastructure is pre-deployed, but a small amount of prior security coordination is expected. Our protocol, authenticated routing for ad hoc networks (ARAN), is based on certificates and successfully defeats all identified attacks.