A Survey of Routing Protocols that Support QoS in Mobile Ad Hoc Networks <s> Summary <s> A mobile ad hoc network (MANET) consists of mobile nodes communicating over wireless channels. Routing in MANETs is very challenging due to the random mobility of nodes and unreliability of wireless channels. Therefore most of the existing routing algorithms make only the best effort to find routes for communication but do not provide any performance guarantee. Because of the widespread use of MANETs in real-time applications, it becomes pertinent to provide deterministic network behavior. Quality of Service (QoS) aims to shape the network behavior and provide performance guarantees. In this work, a novel heuristic called Advanced-Optimised Link State Routing (A-OLSR) protocol is designed to provide QoS. It functions by enhancing the connectivity of nodes and establishing more stable routes as compared to standard best-effort Optimised Link State Routing (OLSR) protocol. The simulation results show that A-OLSR provides lower delay, reduces energy consumption and achieves higher throughput without introducing any additional routing overhead as compared to the standard OLSR and it's variants-A$$'$$?-OLSR and A$$''$$??-OLSR. The results also show that A-OLSR provides scalability since it's performance remains consistent with the increasing size of network. <s> BIB001 </s> A Survey of Routing Protocols that Support QoS in Mobile Ad Hoc Networks <s> Summary <s> Due to resource constraints and dynamic topology of mobile ad hoc networks (MANETs), supporting quality of service (QoS) in MANETs is a challenging task. Although lots of research have been done on supporting QoS in the Internet and other networks, they are not suitable for the MANET environment. While traditional protocol layering is an important abstraction to reduce complexity of network design in wired networks, it is not well suited to wireless networks to provide complex functionalities like QoS due to interdependencies of different layers. This paper provides a brief review of the current researches on QoS support in MANETs specially the different existing QoS models and proposes a general framework which is based on a cross layer approach. A thorough investigation of the different techniques at different layers and their adaptation has lead to this simple framework which gives better performance under different traffic loads and mobility scenarios. <s> BIB002
In this article, we presented a survey of several QoS-aware unicast routing protocols for MANETs. We compared these routing protocols in terms of their support for node mobility, their routing overhead, their requirements for extra node hardware, and their support for scaling of the network. We also pointed out the open issues that must be addressed in QoS-aware routing in terms of bandwidth/delay estimation, route discovery, resource reservation, and route maintenance. This article presented a survey of QoS-aware unicast routing protocols for MANETs. Another important aspect in providing QoS at the routing layer is multipath routing, which provides spatial redundancy in data transmissions. Furthermore, as end-to-end communication is the result of the cooperation of all the network layers BIB001  BIB002  , a cross-layer design is the key to providing QoS to applications in MANETs.