Cisco currently offers (and higher) for free to all Networking Academy members. Here is why you should use the new version instead of 5.1:
Even stable software has quirks. Here are solutions for frequent problems: Cisco currently offers (and higher) for free to
Cisco Packet Tracer 5.1 is a network simulation software developed by Cisco Systems, Inc. It allows users to create and simulate network topologies, configure network devices, and test network behavior. This software is widely used by networking professionals, students, and educators to design, implement, and troubleshoot computer networks. configure network devices
Visit Cisco NetAcad here and get the real, safe, top-tier simulator today. and educators to design