I used to work for a Service Provider that supported over 400 endpoints of everything from Cisco to Tandberg, new and old, 15 separate customer networks inlcuding the infrastructure. I think at last count I managed or had access to 15 video bridges (Codian SD/HD, Polycom MGC/RMX, MPS 200's)
We also supported Vidyo, CMA, Movi, TMS, VCS's, VBP's ... You get the point.
Support team was as follows:
- I was last level of support for the company
- 1 backup administrator who supported me but had other duties as well
- Helpdesk of 5
I think it is important to understand about half the devices were in customer networks where they took the 1st level call. The other half fell to the support desk which was pretty advanced. They had access to the routers and many other devices that most Video Guys do not have. That said there was an entire network team that I loved working with that supported the underlying transport, which I also had access to.
So the numbers may be off a little, but pretty close to what you are looking for I think.