Mitigation of topology control traffic attacks in OLSR networks

Abstract

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 protection compared to the MPR selection with extra coverage presented in RFC3626, but reducing the overhead generated by redundant control information.