Exchange Server 2016 Architecture

The Exchange Server 2016 Architecture builds upon the architecture introduced in Exchange Server 2013, with the continued focus goal of improving the architecture to serve the needs of deployments at all scales.The key change you will notice is the Exchange team removed the Client Access server (CAS) role and added the client access services to the Mailbox role. Even without the CAS role, the system maintains loose coupling in terms of functionality, versioning, user partitioning and geographical affinity. To find out more check out the Exchange Server Team blog.