I have been fortunate to have found my way into the networking industry almost 25 years ago, and to have learned foundational skills which have been amazingly helpful to my career along the way. These are skills in topics like binary, IP Addressing and masking, and BGP. These are some of the fundamental protocols used in every cloud, in every network, and across the internet.
These skills have been built upon and refined over this time, continually sharpening the saw. But learning them provided the platform from which to begin architecting and engineering highly available systems. These cornerstone technologies are best described in two words: pervasive, and fundamental.
There have also been a number of technologies that were learned and became tools for a period, or for a niche environment. Like Openflow, for example. A great protocol for some things (like making a switch not switch), but overly complex for other things (like trying to get a switch to just, switch). That