Cisco Packet Tracer 51 Network Simulation Software Updated Download Top -

M. R. B. de Araujo et al., "Performance evaluation of simulated networks: Limitations of educational network simulators" (journal article)

Cisco Networking Academy: Learn Cybersecurity, Python & More Key Features of Packet Tracer de Araujo et al

Cisco provides the software for free, but it must be accessed through the official Cisco Networking Academy (NetAcad) : Resource Hub: Get Packet Tracer, Virtual Machines, and More and is no longer officially supported or distributed

Cisco Packet Tracer is a powerful, cross-platform network simulation tool designed by Cisco Systems to help students and professionals create network topologies and imitate modern computer networks. de Araujo et al.

A direct search for "cisco packet tracer 5.1 network simulation software download top" will lead you to sketchy forums. We strongly recommend avoiding those.

and is no longer officially supported or distributed by Cisco.