Mobile ad hoc networks (MANETs) are a set of mobile nodes which over a shared wireless medium communicate with each other without the presence of a predefined infrastructure or a central authority. [1]. The absence of a central management agency or a fixed infrastructure is a key feature of MANETs. Security issues in MANET are a challenging task nowadays. MANETs are vulnerable to passive attacks and active attacks because of limited number of resources and lack of centralized authority.

more »

... e attack is an attack in network layer which degrade the network performance by dropping the packets. This paper identifies black whole attack against Optimized Link State Routing (OLSR) protocol, one of the four standard routing protocols for MANETs. We analyze in detail the impact of this attack in order to show the necessity for a countermeasure to guard against the attack.