Manage WAN's with 10,000 nodes. Biggest customer at the moment is Cemex. Tis a bit of a pain fixing monotonous faults all day, but some times interesting stuff pops up its brilliant fun. Recently had a device which was issuing DHCP addresses and causing chaos.
Haha did that to the guys in who handle the office IT for my sister company for a laugh put a DHCP server (netgear router duct tapped under a desk) on the spare cable. They are on 192.168.234.x so i put it in as 10.0.20.x. mean i know but also hilarious.