Professional supports two types of server licenses and the combination
of the two is a third.
Concurrent licenses require that you are connected to the network
every time you start Professional. As one is in use, the total count
is reduced by one. Multiple instances on the same machine do not
deduct from the count.
Distributed licenses also live on YOUR server. The first time you run
Professional, the license is stored on your machine and deducted from
the available server count.
Hybrid licenses allow you to use either mechanism. The distributed
licenses, as they are used, deduct from the available pool of either
concurrent or distributable. Distributed are clearly best for laptops
and concurrent for workstations that are always reliably connected to
the network.
I do not know how the pricing works and it may not be that all types
are available in all geographies. Not my area of expertise(sorry).
Eric Blasenheim
PBBI (MapInfo)