Authors : Mehrdad Manaffar , Hamidreza Bakhshi and Nasser Yazdani
Abstract: Telecommunications services are evaluated by a set of parameters called QoS parameters such as throughput, delay, jitter and packet loss. QoS layered approach separates QoS aspects on each network layer in order to offer the possibility of selection a certain configuration according to network capabilities and correlated with user/application availability. This study analyzes QoS parameters from the network perspective looking on 2 different TCP/IP layers: Transport Layer (TCP and UDP) and Network Layer (DSR, AODV and DSDV). Also, an evaluation on the Impact of different node speeds on QoS Metrics in both Layers will be presented. According to the simulation results, AODV has the best performance even in networks with moving mobile nodes. The On-demand protocols, AODV and DSR perform better than the table-driven DSDV protocol. Although DSR and AODV share similar on-demand behavior, the differences in the protocol mechanics can lead to significant performance differentials. The performance differentials are analyzed using varying network load, mobility and network size. In transport Layer because of UDP�s connection less nature, it doesn�t need any confirmation for receiving data. So, this specification makes UDP protocol suitable in critical-time applications (real-time applications) in comparison with other transport layer protocols such as TCP.
Mehrdad Manaffar , Hamidreza Bakhshi and Nasser Yazdani , 2008. QoS Metrics Evaluation in Two Network Layers in Wireless Ad Hoc Networks . International Journal of Soft Computing, 3: 120-127.