FLEXlm Network License Optimization Calculator
Use the Erlang-C queuing model to find the minimum floating seats needed for your CAD/BIM team. Balance license denial risk against procurement costs.
License Pool Concurrency Grid
Visual seat allocation showing active usage vs queue blocks
By pooling 34 floating seats for 50 users, you reduce hardware/license counts by 16 units, saving 4.8% of your CAD software budget.
Denial Rate Curve
Erlang-C sensitivity analysis curve
Floating Concurrency Setup
Input user metrics and licensing setups
Tolerances & Pool Controls
Define license constraints and wait parameters
Generated FLEXlm Options File Config (options.opt)
Copy-pasteable server-side optimization variables
# FLEXlm Options File — Optimization Generated by CADGuide.tools
# Target Software: AutoCAD (Autodesk)
# Total Users: 50 | Floating Pool Seats: 34
# 1. TIMEOUTALL - Release idle licenses automatically after 15 mins inactivity (900s minimum)
TIMEOUTALL 1080
# 2. BORROW_LOWWATER - Keep seats at server, prevent users from borrowing all seats offline
BORROW_LOWWATER adsk_sds 10
# 3. MAX_OVERAGE_LIMIT - Block seat camping by specific user segments
# GROUP cad_contractors user_temp1 user_temp2
# MAX 2 adsk_sds GROUP cad_contractors
# 4. DEBUGLOG - Route diagnostic denials report locally
DEBUGLOG /var/log/flexlm_denials.logQueuing Theory & FLEXlm Allocation Guide
1. How Erlang-C Models Floating Licenses
Floating CAD licensing is a classic M/M/m queuing system. There are m identical servers (licenses) available to a finite group of users. When an engineer launches AutoCAD or SolidWorks, they request a license from the server.
If a seat is available, they checkout the license and start drafting. If all seats are in use, the request is denied. In Erlang-C queuing models:
- Offered Load (A): The average number of concurrent licenses requested, measured in Erlangs.
- Denial Probability (Pc): The probability that a user launching CAD is denied a seat and must wait in a queue or try again later.
Erlang-C assumes that if all licenses are checked out, users queue until one becomes available. If users abandon the request, it behaves as an Erlang-B model (loss system). Most IT managers use Erlang-C to represent a worst-case delay scenario.
2. Reducing License Camping via options.opt
The primary weakness of floating licenses is license camping: users leave AutoCAD open overnight or during lunch, unnecessarily holding a seat.
To mitigate this, licensing managers configure the options.opt file on the license server:
- TIMEOUTALL 900: Reclaims the license if the client machine is idle for more than 15 minutes (900 seconds). Standard practice.
- BORROW_LOWWATER: Restricts borrowing seats for offline laptops, ensuring a minimum pool remains active on the local server.
- EXCLUDE / INCLUDE: Prevents non-drafting personnel from accidentally holding seats, reserving them for core engineers.
Deploying these configuration values allows IT teams to reduce pool sizes and achieve maximum procurement savings.
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