You need to identify the items that have a cost on-premise and that will be rolled into the
service in the cloud. Compute hardware costs and data center security costs will be rolled
in the service cost in the cloud so you need to include them in the model so you can really
understand the true TCO on-premise vs. the cloud
Firewall management, application licensing and operating system patching need to be paid for
on-premise and in the cloud so there is little difference