[cisco-voip] CallManager Licensing Scheme

[John Lewis]

I would like to setup a callmanager with one publisher, two subscribers, and 
one backup subscriber.  There will be a total of maybe 500 users.

Is  the licensing on  a per cluster or per server basis?  That is, will I 
need to buy 1 (2500) user count license for the entire cluster, or 4 (2500) 
user count licesnses(one for each server)? Or some mix there in such as for 
active subscribers only?

I have scoured both the internet and cisco's website and cannot find 
licensing info anywhere.

Thanks.