Comparative Performance of Hierarchical Fault Tolerance Protocol for Mobile Agent Systems

A Mobile Agent (MA) is autonomous and identifiable software process that travel through a network of heterogeneous machine and act autonomously on behalf of user. Improving the survivability of MA in presence of various faults is the major issue concerns with implementation of MA. This paper presents a brief introduction of Hierarchical Fault Tolerance Protocol (HFTP) for Mobile Agents, which can tolerate host failure, system failure as well as link failure by grouping the hosts within a network and rear guard based migration of MA in the global network. A CPN model of HFTP has been used to generate simulation results for different scenarios by using various monitoring and data collection tools provided by CPN. The parameter used for analysis is trip time (time required by MA to complete its itinerary) and network overhead (number of packets transfer required over network). In order to check the efficiency of HFTP, we have modeled two other protocols Progressives Fault Tolerance Mechanism (PFTM) based of rear guards and Server Group based Agent Recovery Protocol (SG-ARP) with which our model is inspired. Performances of HFTP, PFTM and SG-ARP are compared on the basis of data obtained from simulations for different fault cases. The results of the simulation have been presented and analyzed. Keywords-Mobile Agents, Fault Tolerance, Colored PetriNet