The document discusses defense mechanisms against flooding attacks in mobile ad hoc networks (MANETs). It begins with broad background on networks and network security. It then discusses specific areas including MANETs and flooding attacks. The document reviews several papers from 2008-2011 on related topics. It discusses methodologies, advantages and drawbacks of approaches for detecting and preventing flooding attacks in MANETs, including using period-based mechanisms, trust-based classification of nodes, and probabilistic broadcasting. The comparative study section provides brief summaries of several papers analyzing defenses against flooding attacks in MANETs.