Packet Loss in Mobile Ada Hoc Networks

Abstmct-We investigate packet loss in mobile ad hoc networks via simulation. Ad-hoc on-demand distance vector (AODV) and destination-sequenced distance vector (DSDV) are chosen as representatives of the on-demand and proactive routing protocols respectively. The effects of congestion and mobility in various network contexts are explored. The results indicate that DSDV loses 10% to 20% more packets than AODV does for UDP traffic. For TCP traffic, the packet loss for DSDV is a half of that for AODV. Mobility is the dominant cause for AODV, which is responsible for more than 60% of total packet loss. For DSDV, more than 50% of total packet loss is congestion-related. Sample data shows that the packet loss distribution over time is bursting, which makes the tradition Poisson framework unsuitable for modelling it. Preliminary results exhibit self-similar pattern that leads us to believe that fractal model is promising to describe packet loss in ad hoc networks. This work provides guidelines for the design of routing and flow control algorithms and insights in choosing proper parameters in future simulation and analytic studies. Throughput is generally accepted as one of the most important metrics to evaluate the peiformance of a routing protocol. Several simulation-based performance comparisons have been done for ad hoc routing protocols in the recent years. S.R. Das et al. evaluate perfoimance of ad hoc routing protocols based on the number of conversations per mobile node [ I]. The performance comparison of two on-demand routing protocols: dynamic source routing (DSR) [2] and AODV [3] is presented in [4]. The performance o f t w o location-based routing protocols for ad hoc networks is investigated in 151. An adaptive distance vector routing algorithm is proposed in [6], and its performance. compared with AODV and DSR, is studied. Although various throughput results in different network contexts have been obtained. the causes for throughput variation in ad hoc networks has not been deeply understood. Packet loss is one thrust to study throughput, since thl.oughput is deteimined by how many packets have been sent and how many packets have lost. Packet loss in wired network has been investigated. For example. a single server queueing system with a finite buffer capacity is used to analyze packet loss processes in high-speed networks in [7]. The end-to-end packet delay and loss behaviors in the Internet are studied using the UDP echo tool in [S]. These work target at the packet loss due …