EVALUATIN OF QoS PARAMETERS ON TCP/IP IN WIRELESS AD HOC NETWORKS

Wireless ad hoc network is a collection of mobile n odes interconnected by multi-hop communication paths forming a temporary network without the aid of any centralized administration or standard support serv ices regularly available as in conventional networks. Th e topology of the network changes dynamically as mobile nodes join or depart the network or radio li nks between nodes become unusable. To accomplish this, a number of ad hoc routing protocols have bee n proposed and implemented, which include Destination Sequenced Distance Vector (DSDV), Dynamic Source Routing (DSR) and Ad hoc On-demand Distance Vector (AODV) routing protocols. In this paper, the se protocols are evaluated by a set of parameters s uch as throughput, delay, packet loss, etc., and we ana lyze the Quality of Service (QoS) parameters from t he network perspective looking into two different TCP/ IP layers: transport layer and network layer. The impacts of node loads on different QoS metrics in b oth layers are evaluated too. As the simulation res ults suggest, AODV demonstrates the best performance even in the 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 mechanisms can lead to significant performance differentials. The performa nce differentials are analyzed using varying networ k load, mobility and network size. In transport layer , because of UDP's connectionless nature, it does n ot need any confirmation for receiving data, which makes UDP protocol suitable in critical time applicati ons (real time applications) in comparison with other t ransport layer protocols such as TCP.