Whatever “Cloud” can mean for you, if you have an Enterprise Agreement or another Volume Licensing Agreement, please consider that you will have to rethink the way you are licensed to day. There is no plane elevating perpetual licenses to the cloud, you have to subscribe to additional licenses to access for example the Microsoft cloud. You can create a private cloud with your existing licenses however this may not correspond to the total outsource and painless fully licensing on demand you are pursuing. The key to the solution is the hosted provider, how you engage that provider and the services offered. A cloud solution that enables you to strategize instead of spending many hours dealing with licensing issues is what I envision is going to happen in the near future Are you ready for the battle of the transition?, you must identify how to leverage existing licensing investments or make a better one. For example, you own Core CAL and would like to add Lync but the cost of going ECAL is too much or inconvenient, what about outsourcing Lync to the cloud with full features available?. My advice, be careful on the features available on public cloud, compare it to a private cloud and move to the dynamic mode instead of dealing with legacy licenses and compliance issues.