Cisco Packet Tracer is a software tool for network simulation. You can use it to design both simple and relatively complex network topologies. You can also configure virtual machines, routers, commutators and other network devices to check network topologies in Packet Tracer.
Cisco Packet Tracer can also simulate wireless networks, VoIP networks and many others.
If you aim at Cisco certification (e.g. CCENT, CCNA, etc.), you can use Cisco Packet Tracer to configure Cisco network devices (such as commutators and routers) via Cisco IOS.
Cisco Packet Tracer is free to download. All you need is registration to Cisco Network Academy. You can create a Cisco Network Academy account for free.
In Packet Tracer 7, a user authentication feature has been introduced. A Network Academy user must log in at the first launch of Packet Tracer. Unregistered users can save their topologies three times only. However, they can use a guest access button to sign up for a free self-education course "Introduction to Packet Tracer" and get a netacad.com account with full access to Packet Tracer. "Introduction to Packet Tracer" course will help you to familiarize yourself with basic Packet Tracer features.
To create a Cisco Network Academy account, proceed to https://www.netacad.com/courses/packet-tracer/introduction-packet-tracer and see the following page. Click Sigh up today! to download Packet Tracer.
Select English in the dropdown menu. Fill in the form and click Submit.
After you sign up and confirm your account, proceed to https://www.netacad.com/ to the following page. Click Log In -> Login.
After you log in, click Resource -> Download Packet Tracer in the menu.
On this page, select and download the required version (for Windows, Linux, MacOS, Android or iOS).
Install and run. Use you netacad account to sign in upon the first launch. To sign in without an account, click Guest Login in the right bottom corner of the screen, wait for the countdown and click Confirm Guest button.
That’s it! Now you can begin.