How many users or Crux devices would I require for my need?
Each Crux LX unit can connect up to 250 users and with 20 concurrency in an office setup (assuming average office use with 10% concurrency based on active users).
Each Crux VX unit can connect up to 250 users with 30 concurrency in an office setup. In a Call Centre setup, one can plan for up to 30 agents on one Crux VX box (assuming 100% utilization).
Theoretically, one can configure thousands of extensions on a single unit of Crux, if the unit is being used only as an IP-PBX and not as a data router. Browsing needs and patterns can be very different, especially if audio visual content is permissible. The limiting factor however is the expected concurrency.
Each Crux LX unit can support up to 20 concurrent conversations and Crux VX up to 30 concurrent conversation using a g.711a (alaw) / g.711u (ulaw) codecs. If the codec is selected as g.729 (included in Crux) on Crux and all end points, then the concurrency can be expected to increase by 2-3 times, depending on user load and call volume.
It is best to plan for multiple Crux devices if you expect to connect more than 250 users or require more concurrency. You may also require some additional access points to span the space to connect large number of users who may have a mixed usage (Crux as well as regular browsing needs).