Uploaded October 2025 | Updated September 2026, 2 weeks ago

---

"The best-laid plans of mice and men often go awry" - as the ISO team were designing a beautiful, structured layered model, people were already building their own. Dr Richard G Clegg of Queen Mary University London explains the network layers model.

Computerphile is supported by Jane Street. Learn more about them (and exciting career opportunities) at: jane-st.co/computerphile

This video was filmed and edited by Sean Riley.

Computerphile is a sister project to Brady Haran's Numberphile. More at bradyharanblog.com