Showing papers by "Samir R. Das published in 1998"

Comparative performance evaluation of routing protocols for mobile, ad hoc networks

Abstract: We evaluate several routing protocols for mobile, wireless, ad hoc networks via packet level simulations. The protocol suite includes routing protocols specifically designed for ad hoc routing, as well as more traditional protocols, such as link state and distance vector used for dynamic networks. Performance is evaluated with respect to fraction of packets delivered, end-to-end delay and routing load for a given traffic and mobility model. It is observed that the new generation of on-demand routing protocols use a much lower routing load. However the traditional link state and distance vector protocols provide, in general, better packet delivery and delay performance.

Combining optimism limiting schemes in time warp based parallel simulations

Abstract: The time warp protocol is considered to be an effective synchronization mechanism for parallel discrete event simulation (PDES). However, it is widely recognized that it suffers over-optimistic behavior on the part of the simulation processes that may be very harmful for performance. In current literature, two techniques have been used to counteract this problem: throttling of over-optimistic processes; and scheduling or load balancing. However, the study of these techniques has been primarily done in isolation. We demonstrate using a parameterized simulation model of time warp that an appropriate combination of throttling and global scheduling using LP migration can be very beneficial for performance compared to any one of these schemes acting in isolation. This study forms the basis of the design of more powerful control schemes that use a combination of multiple techniques.