2014 called. They have a copy of that .pdf you’re loooking for.
One drawback of having all of the Internet’s resources available is that sometimes these resources move or go away. Usually, a quick Google search can find what you’re after — unless it’s a particular paper on a particular topic that was referenced in a course you’re co-teaching. Then, it has to be that particular paper.
Well, times change, companies update their offerings, and old links get broken. Fortunately, we have a powerful weapon against such things — the Internet Archive’s “Wayback Machine.”
Think of it like a time machine for the Internet. You put in the URL that you’re looking for, and the Wayback Machine searches its archives for that URL. If it finds a match, you often get a choice of snapshots, allowing you to see how the site has changed (or not) over time.
Occasionally, it even has that obscure Cisco .pdf on Industrial Ethernet that you were looking for.