So you need to calculate how much bandwidth Lync will use, you launch google and type “Lync bandwidth requirements”. You click the top link for Microsoft Downloads “Lync 2010 and 2013 Bandwidth Calculator” here http://windowspbx.blogspot.co.uk/2012/01/simple-smb-lync-bandwidth-calculator.html. You download the zip, open the excel file then realise you don’t have a degree in quantum physics or it’s Friday and you just want some quick figures to work with.
Behold Matt Landis’ “Very Simple SMB Lync Bandwidth Calculator” here: http://windowspbx.blogspot.co.uk/2012/01/simple-smb-lync-bandwidth-calculator.html
Obviously it’s not as detailed or accurate as the Microsoft calculator but good to find a ball park figure for one branch office.