An ad-hoc network has a provision of Quality of Service (QoS) to support many applications like digital and multimedia applications. However, one of the challenging tasks in ad-hoc network is Quality of Service (QoS) which is determined by numerous parameters such as bandwidth, delay constraints, varying channel conditions, power limitations, node mobility, dynamic topology, packet delivery ratio, end-to-end delay and connection duration. With the increasing demand for real time applications in the Wireless Senor Network (WSN), real time critical events anticipate an efficient Quality-of-Service (QoS) based routing for data delivery from the network infrastructure. Designing such QoS based agent routing protocol to meet the reliability and delay guarantee of critical events while preserving the energy efficiency is a challenging task. This paper surveying about QoS based agent routing algorithms in MANET, WSN and VANET.