Cisco Packet Tracer
Simulates the network behavior while providing advanced packet analysis and simulation, as well as visualization, authoring, and assessment of the network components. Support drag-and-drop functionality to easily add network devices to the organization you're developing the network or for pure learning.
Download Cisco Packet Tracer 220.127.116.117 from our website for free. This free software was originally designed by Cisco Systems. The software lies within Internet & Network Tools, more precisely Network Tools.
From the developer:
acket Tracer 5.1 is the latest version of Cisco Networking Academy’s comprehensive networking technology teaching and learning software. Innovative features of Packet Tracer 5.1, including powerful simulation, visualization, authoring, assessment, and collaboration capabilities, will help students and teachers collaborate, solve problems, and learn concepts in an engaging and dynamic social environment
You may want to check out more software, such as Cisco PacketTracer, Colasoft Packet Player or Cisco CLI Analyzer, which might be related to Cisco Packet Tracer.