Think of a named user license as “owned” by and used exclusively by the SalesLogix user assigned to it. Even if that user is not logged in at the time, their assigned named license is not available to be used by others users. The up-side to this type of license is that the named user will always be able to log into the software regardless of how many other users may be logged in since his license is held in reserve just for him.
A concurrent license or group of concurrent licenses is a “pool” of licenses that can be used by an unlimited number of SalesLogix users who are assigned to use the pool. When a user assigned to the concurrent license pool tries to log in, SalesLogix checks to see if there is a concurrent license available and if so, they successfully log in. If all of the concurrent licenses in the pool are in use by other logged in users, the user attempting to log in gets an error message stating that there are no concurrent licenses in the pool available at this time and to try again later.
The up-side to concurrent licenses is that they are shared and therefore less costly to buy licenses for users who work on shifts or are just casual users who don’t need to stay logged in for long periods of time or their need to log in is not time sensitive or urgent. The down-side is that a user who needs to log in may not be able to in the case where the number of concurrent licenses in the pool is equal to the number of users currently logged in.
Another way to think of a named user license is like having a reserved parking space in the parking lot. The named user always has his designated space available whether his car is currently on the lot or not. The rest of the parking spots are like a concurrent user license where first come first served and if a shared spot is open when you arrive, you can park there and if no spaces are open, you get to drive around until someone leaves the lot.