DEVS-NS2 Environment: An integrated tool for efficient network modeling and simulation

This paper presents a new DEVS/NS-2 modeling and simulation environment which supports both high and low levels of abstraction for network m odeling and sim ulation. DEVS (Discrete Even t System Specification) is a well-defined m athematical f ormalism specif ication for structure and behavior of dynamic system s. The NS-2 is a discre te event network simulator, whose primary use is intended to build and run various detailed network m odels and protocols such as TCP/IP, satellite links, and wireless networks. By combining the two powerful modeling and simulation systems, the significant benefits attained by the interoperabl e sim ulation of DEVS and NS-2 are reduction of the cost, increased hi gh and low level m odeling power, and enhanced r eusability. To integ rate the sys tems seam lessly, two major challenges are add ressed. The firs t cha llenge is to synchronize the different ways of handling event schedules by th e two simulation system s. This paper illustrates h ow the s imulation tim e advances of DEVS and NS-2 are synchronized with each other. The latte r problem is related to assign ing th