I worked for Microsoft for the last 20 years on service and server infrastructure for large scale onprem and online deployments. I was part of the teams that build products like Active Directory, DNS, Identity Management (MIIS/FIM), OCS/Lync. For the last couple of years I have been focusing on delivering Lync experiences as part of Office 365 with aspects covering provisioning, reliability and enabling migrations from on premise to on line.