With the Lync Server 2010 Bandwidth Calculator, you can enter
information about your users and the Lync Server features that you want
to deploy, and the calculator will determine bandwidth requirements for
the WAN that connects sites in your deployment. The package contains a
Microsoft Excel spreadsheet that calculates WAN bandwidth requirements
for a Lync Server deployment based on administrator-specified user
profiles and network information, and a Word document user guide that
accompanies the spreads
Download it from there: http://www.microsoft.com/en-us/download/details.aspx?id=19011
Read more at source: http://blogs.technet.com/b/fmustafa/archive/2013/05/14/lync-2010-and-2013-bandwidth-calculator.aspx
Cheers,
Anderson Patricio
http://blogs.msexchange.org/patricio
http://www.andersonpatricio.ca
Twitter: @apatricio