Delay aware Reactive Routing Protocols for QoS in MANETs: a Review

Mobile Ad Hoc Networks (MANETs) are wireless networks, which do not require any infrastructure support for transferring data packets between mobile nodes. These nodes communicate in a multi-hop mode; each mobile node acting both as a host and router. The main function of Quality of Service (QoS) routing in MANETs is to establish routes among different mobile nodes that satisfy QoS requirements such as bandwidth, end-to-end delay and to be able operate within the limited energy constraints. Efficient QoS routing protocols are required by most commercial, real-time and multimedia applications. Ad Hoc On-Demand Distance Vector (AODV) and Dynamic Source Routing (DSR) protocols are two of the most on-demand protocols used in MANETs. These protocols use shortest path as a main metric to establish routing between source and destination. However, they are designed primarily as best effort services and as such they do not fully heed QoS requirements as required by MANETs. This paper presents an overview of reactive routing protocols in QoS which use delay as a main metric.