In this paper, the authors focuses on performance evaluation of reactive, proactive and hybrid MANET (Mobile Ad hoc NETwork) routing protocols, namely AODV, DSR, OLSR and GRP. OLSR is designed to work in a completely distributed manner and does not depend on any central entity. The AODV (Ad-hoc On demand Distance Vector) protocol consists of two important mechanisms, route discovery and route maintenance. It is designed to be self-creating in an environment of mobile nodes, withstanding a variety of network behaviors such as a node movement, link failures and packet losses. The GRP is not so much a distinct protocol as it provides a framework for other protocols.