Zahra Safari Khosroabadi - Department of Computer Engineering, Payame Noor University, Tehran. IRAN
Bita Amirshahi

Wireless Sensor Networks (WSNs) are wireless networks, which to transmit packets between sensor nodes does not require any infrastructure.each sensor node acting both as a host and router. To quantitatively measure quality of service, several related aspects of the network service are often considered, such as error rates, bit rate, throughput, transmission delay, availability, jitter, etc. The main function of Quality of Service (QoS) routing in WSNs is to establish routes between different sensor nodes that ability to maintain Quality of Service (QoS) requirements such as bandwidth, end-to-end delay and to be able operate within the limited energy constraints. Ad Hoc On-Demand Distance Vector (AODV) and Dynamic Source Routing (DSR) protocols are two of the most on-demand protocols used in WSNs. Reactive (or on-demand) routing protocols find a path between the source and the destination only when the path is needed (i.e., if there are data to be exchanged between the source and the destination). These protocols use shortest path as main metric to establish routing between source and destination. This paper presents an overview of reactive routing protocols in QoS which use delay as a main scale.

Quality of Service, WSNs,end-to-end delay