Cisco Packet Tracer is a network simulator that can be used not just by students but also by instructors and network administrators. This software provides a wide range of Cisco switches and routers running on IOS 12 and IOS 15, wireless devices from Linksys, and several end devices such as PCs and servers with a command line. It is more than just a simulator and provides physical simulation as well as an assessment tool. The assessment tool can be used to create practical networking questions with a complex scoring model. The physical workspace provided can be used to determine the range of wireless devices.

For windows 32 bit :  http://lebsiting.com/academic/networking/Packet Tracer 7.2 for Windows 32 bit.zip