I was recently interviewed for a new network career site—
I started out building small networks on a lot of different technologies in the USAF, primarily Banyan Vines and Novell Netware, over Token Bus, Thicknet, and other technologies. We implemented a fiber backbone, and I helped replace the old physical switch telephone system main frame with a modern (at that time) SS7 based design. After this, I worked for a small Value Added Reseller around New York City, and then the ASME as a network administrator, then at BASF in the Advanced Technology Group. At this point my wife and I moved to Raleigh, and I started at Cisco TAC in the hardware team. From there I moved to the Routing Protocols team, then Global Escalation, and then into engineering in various roles around Cisco IOS Software and XR. After Cisco, I moved to Verisign Labs, where I primarily focused on security in a more research oriented role, then to Ericsson, working on IPOS, and now LinkedIn.
This looks like a great resource, worth following.