About Step by Packet
Step by Packet is a free collection of animated guides to network protocols and to the tools that automate them. Each guide shows what actually travels between devices, in what order, and why.
How a guide works
Every mechanism has its own animation on a small topology. You can pause it, go back a step or change the speed, and the configuration lines that matter at each step are highlighted next to it. The configurations cover IOS-XE, IOS-XR and NX-OS where the platforms differ; the automation guides use the formats and tools themselves: JSON, YANG, Python, Ansible and the rest.
Where a single setting changes the outcome, a simulator lets you change it yourself. Around the animations you'll find exam notes in five colours, a glossary, a recap, and one analogy that follows the whole topic, with a note on where it stops working.
Who makes it
Step by Packet is made by Madalin, who is working through the Cisco certification path, from CCNA toward CCIE.
Corrections
If something is wrong or unclear, write to contact@stepbypacket.com with the page and the section number.
Independence
Step by Packet is independent. It isn't affiliated with Cisco or with any other vendor, and the exam notes are based on the public exam topics, not on exam content.