One of the papers I authored back in June of 2008 was the following whitepaper, published through Microsoft.  http://www.microsoft.com/downloads/details.aspx?familyid=5ec060fd-ba9a-4c52-8bd8-148f502b791f&displaylang=en  It references a bandwidth calculator that I created and have posted as a link to this blog.  The calculator is just in Beta form and only covers OCS 2007 scearnios.  It may contain bugs and there are some limitations, such as lack of support for time zone considerations and not factoring address book download.  It also requires fairly intimate knowledge of OCS scenarios, so you wouldn't want a customer to fill this out without some guidance.  If you have any customers that need guidance on bandwidth planning, let me know and we'd be happy to assist.

We're currently working on an R2 offering that will take this spreadsheet to the next level.  I'll keep you posted when I have more concrete details on that.

 -Alan

BW Calculation v1.0 Beta.xlsx (350.50 kb)