Hybrid routing protocol using Core Gateway Relay in MANETs

A MANET (Mobile Ad hoc NETwork) is a network with the features of infrastructure-less, multi-hop, self-configuring, and distributed-routing, which are quite different from a traditional wired network. Since nodes in a MANET are free to move, causing the topology of the MANET to change frequently, a routing protocol able to accommodate the rapidly changed topology is required. The MANET routing protocols can be classified into three categories based on routing information update mechanism: (1) proactive/table-driven protocol (2) reactive/on-demand protocol (3) hybrid protocol. Each category has its own advantages and disadvantages. Among these, the hybrid protocol tries to combine the advantages of proactive and reactive ones. This work presents a novel hybrid routing protocol - CG2R (Core Gateway Relay Routing Protocol). The CG2R partitions a network into several regions called zones. The proactive mechanism is used within the zone, while the reactive one is applied outside the zone. Each zone contains at least one core gateway. The core gateway covers more cells and manages more nodes than the general gateway to reduce the possibility for a node moving out the zone. Based on this feature, the core gateways hereby constitute the backbone of the routing path. Unlike conventional cluster-based routing protocols which rely on the algorithm using certain factor such as ID number or Weight to elect cluster heads, in CG2R, the node itself can decide it is a core gateway or not by using the algorithm we devise. The simulation results reveal that CG2R is more scalable and efficient than CGSR and AODV protocols.