QoS and security in Link State Routing protocols for MANETs

Abstract—We study security issues in the Optimized Link State Routing (OLSR) protocol with Quality-of-Service (QoS). We propose the function k-robust-QANS, to construct a Quality Advertisement Neighbor Set (QANS). Given a node v, the one-hop nodes selected as part of its QANS generate routing information to advertise, when possible, a set with k+1 links to reach any two-hop neighbor. Several approaches have been proposed to construct a QANS. However, none of them guarantees that the best links are advertised. A mechanism is presented for QANS construction with guarantee that the best links are advertised with respect to a given routing metric. We present the unadvertised quality links problem when QoS is considered. We also address the slanderer attack, i.e., a misbehaving node that advertises incomplete routing information. Our goal is to find a tradeoff between security and amount of information disseminated. We conduct simulations that confirm our claims

Preventing the cluster formation attack against the hierarchical OLSR protocol

The Hierarchical Optimized Link State Routing (HOLSR) protocol enhances the scalability and heterogeneity of traditional OLSR-based Mobile Ad-Hoc Networks (MANETs). It organizes the network in logical levels and nodes in clusters. In every cluster, it implements the mechanisms and algorithms of the original OLSR to generate and to distribute control traffic information. However, the HOLSR protocol was designed with no security in mind. Indeed, it both inherits, from OLSR, and adds new security threats. For instance, the existence of misbehaving nodes can highly affect important HOLSR operations, such as the cluster formation. Cluster IDentification (CID) messages are implemented to organize a HOLSR network in clusters. In every message, the hop count field indicates to the receiver the distance in hops to the originator. An attacker may maliciously alter the hop count field. As a consequence, a receiver node may join a cluster head farther away than it appears. Then, the scalability properties in a HOLSR network is affected by an unbalanced distribution of nodes per cluster. We present a s

Mitigation of topology control traffic attacks in OLSR networks

The core of the Optimized Link State Routing (OLSR) protocol is the selection of Multipoint Relays (MPRs) as a flooding mechanism for distributing control traffic messages. A node in an OLSR network, selects its MPR set such that all two-hop neighbors are reachable through, at least, one MPR. However, if an MPR misbehaves during the execution of the protocol, the connectivity of the network is compromised. Additional coverage in the selection of the MPRs helps to mitigate the effect of control traffic attacks. RFC3626 defines the selection of MPRs with additional coverage. Nevertheless, the overhead of the network increases due to the added number of control traffic messages. In this paper, we propose an improved MPR selection with additional coverage. Every node selects, if it is possible, k + 1 disjoint MPR sets. The union of those sets, is a k-robust-MPR set. Thus, given a node, alternative paths are created to reach any destination two-hops away. We test both approaches against two kinds of adversaries misbehaving during the execution of the protocol. Our proposed MPR selection with additional coverage mitigates the effect of control traffic attacks by offering equivalent protectio

A new analytic model for the cognitive radio jump-stay algorithm

In cognitive radio networks, primary users have priority over the regulated radio spectrum. Secondary users may use residual air time. We focus on the problem of meeting on a common channel by a group of secondary users. The goal is to make the users rendezvous on a common channel in a minimum amount of time. The jump-stay algorithm has been created by Lin et al. to solve this problem. We construct a new analytic model for the two-user expected time to rendezvous in the jump-stay algorithm that better reflects its performance. For the sake of comparison, we also evaluate the performance of the jump-stay algorithm through simulation

Mitigation of flooding disruption attacks in hierarchical OLSR networks

The Hierarchical Optimized Link State Routing (HOLSR) protocol was designed to improve scalability of heterogeneous Mobile Ad-Hoc Networks (MANETs). HOLSR is derived from the OLSR protocol and implements Multipoint Relay (MPR) nodes as a flooding mechanism for distributing control information. Unlike OLSR, nodes are organized in clusters and implement Hierarchical Topology Control (HTC) messages for inter-cluster communications. Nevertheless, HOLSR was designed without security measures. Therefore, a misbehaving node can affect the topology map acquisition process by interrupting the flooding of control information or disturbing the MPR selection process. We present a taxonomy of flooding disruption attacks, that affect the topology map acquisition process in HOLSR networks, and preventive mechanisms to mitigate the effect of this kind of attacks