Downloads
This section contains resources produced by Capacitas as part of our programme to support and promote performance and capacity management across the ICT industry.Capacitas Excel Add-In
Capacitas has developed a free Microsoft Excel Add-In to support analytical modelling of ICT systems using Excel worksheet functions.
The Capacitas Excel Add-In works under both Excel 2003 and 2007 and contains the following six worksheet functions:
- An Erlang C function to estimate the probability that all of a number of servers are busy at a given average load per server
- A function to estimate response times (either with or without service time) for a system that may be approximated by an M/M/N queuing model
- A function to estimate response times (either with or without service time) for a system that may be approximated by an M/G/1 queuing model
- A function to estimate response times (either with or without service time) for a system that may be approximated by an M/G/N queuing model
- An Erlang B function to estimate the probability of call dropping based on a number of lines and the load
- A function that uses the Erlang B function to predict the number of lines required to achieve a particular grade of service based on an assumed load
Contents
capacitas.zip contains the following files- CAPACITAS.xla - the Excel Add-In
- Capacitas Queuing Examples.xls - an Excel spreadsheet that describes the use of each function, along with an example
- licence.txt - the licence agreement
Installation Instructions
Follow these steps to download and install the Capacitas Excel Add-In:
- Click on capacitas.zip to download the Add-In
- Unzip and save CAPACITAS.xla into the appropriate Add-Ins directory (for example, C:\Program Files\Microsoft Office\Office\Library or C:\Documents and Settings\UserName\Application Data\Microsoft\AddIns)
- Start Microsoft Excel
- If you are using Excel 2003 then select 'Add-Ins...' from the 'Tools' menu
- If you are using Excel 2007 then click the Office Button in the top left hand corner and select 'Excel Options' from the menu
- Then highlight 'Add-Ins' on the left hand menu and click 'Go..." at the bottom of the screen next to 'Manage: Excel Add-ins'
- The remainder of the process is the same for both Excel 2003 and 2007
- Click the 'Browse...' button, manually locate CAPACITAS.xla and click 'OK'
- Check the 'Capacitas Functions' checkbox and click 'Ok'
- You are now ready to begin using the Capacitas queuing functions
- Open the 'Capacitas Queuing Examples.xls' workbook to see examples of the queuing functions in use
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