A Review and Comparison of Quality of Service Routing in Wireless Ad Hoc Networks

Quality of Service (QoS) guarantees must be supported in a network that intends to carry real time and multimedia traffic. IETF RFC 2386 defines QoS as a set of service requirements to be met by the network while transporting a packet stream from source to the destination. The dynamic network topology and wireless bandwidth sharing makes QoS provisioning far more challenging in wireless networks as compared to the wired counterparts. The support for the QoS services is underpinned by QoS routing. A QoS routing protocol selects network routes with sufficient resources for the satisfaction of the requested QoS parameters. The goal of QoS routing is to satisfy the QoS requirements for each admitted connection, while achieving global efficiency in resource utilization. The problem of QoS routing with multiple additive constraints is known to be NP-hard. This requires the QoS dynamics to be fully understood before it can be implemented in wireless ad hoc networks. The paper discusses the issues involved in QoS routing and presents an overview and comparison of some existing QoS routing protocols. The article concludes with some open issues for further investigation.