Packet Tracer offers an effective, interactive environment for learning networking concepts and protocols. Most importantly, Packet Tracer helps students and instructors create their own virtual “network worlds” for exploration, experimentation, and explanation of networking concepts and technologies.
Cisco Packet Tracer 8.1. 1 can be downloaded for FREE from official Cisco Netacad website. Log in to Cisco Netacad.com learning website and select Resources > Packet Tracer in the menu to access the download page.