Mobile Ad-hoc Network (MANET) is the most demanding field in the area of wireless networks. MANET has mobile devices or users which are generally known as nodes each one of which is equipped with radio transmitter and receiver. MANET is a temporary network of wireless mobile nodes that has no fixed infrastructure. A key issue is a necessity that the Routing Protocol must be able to respond rapidly to the topological changes in the network. Topology management plays a vital role prior to the actual routing in MANET. Cluster-based structure (hierarchical structure) in net-work topology has been used to improve the routing efficiency in a dynamic network. Clustering in mobile ad hoc networks plays a vital role in improving resource management and network performance (routing delay, bandwidth consumption, and throughput). Major problems in routing are Asymmetric links, Routing Overhead, Interference, and Dynamic Topology. Routing in MANETs has been an active area of research and in recent years numerous protocols have been introduced for addressing the problems of routing.