The below is preliminary information and subject to change before the first release of Exchange server 2016
1- The Block Architecture:
In Exchange 2013 , there were 2 blocks (CAS – MBX) , these both blocks has been merged in Exchange 2016 , there is a single building block that provides the client access services and the high availability architecture necessary for any enterprise messaging environment.
The Mailbox server role now:
- Houses the logic to route protocol requests to the correct destination endpoint.
- Hosts all of the components and/or protocols that process, render and store the data.
No clients connect directly to the back-end endpoints on the Mailbox server; instead, clients connect client access services and are routed (via local or remote proxy) to the Mailbox server that hosts the active database that contains the user’s mailbox.
DAGs in Exchange Server 2016 do have a few specific enhancements:
- DatabaseAvailabilityGroupIpAddresses is no longer required when creating a DAG. By default, the failover cluster will be created without an administrative access point, as this is the recommended best practice.
- Replay Lag Manager is enabled by default.
- Lagged database copy play down can be delayed based on disk latency, thereby ensuring active users are not impacted.
- Database failovers times are reduced by 33% when compared to Exchange Server 2013.
Communication between servers still occurs at the protocol layer, effectively ensuring that every server is an island. For a given mailbox’s connectivity, the protocol being used is always served by the protocol instance that is local to the active database copy.
The load balancer configuration is also not affected by this architectural change. From a protocol perspective, the following will happen:
- A client resolves the namespace to a load balanced virtual IP address.
- The load balancer assigns the session to a Mailbox server in the load balanced pool.
- The Mailbox server authenticates the request and performs a service discovery by accessing Active Directory to retrieve the following information:
- Mailbox version (for this discussion, we will assume an Exchange 2016 mailbox)
- Mailbox location information (e.g., database information, ExternalURL values, etc.)
- The Mailbox server makes the decision to proxy the request or redirect the request to another Mailbox server in the infrastructure (within the same forest).
- The Mailbox server queries an Active Manager instance that is responsible for the database to determine which Mailbox server is hosting the active copy.
- The Mailbox server proxies the request to the Mailbox server hosting the active copy
2- Search Improvements
One of the challenging areas for on-premises environment was the amount of data that was replicated with each database copy in previous releases. In Exchange Server 2016, we have reduced bandwidth requirements between the active copy and a passive copy by 40%. This was accomplished by enabling the local search instance to read data from its local database copy. As a result of this change, passive search instances no longer need to coordinate with their active counterparts in order to perform index updates.
Another area of investment in search has been around decreasing the length of time to return search results, especially in online mode clients like OWA. This is accomplished by performing multiple asynchronous disk reads prior to the user completing the search term, which populates the cache with the relevant information, providing sub-second search query latency for online mode clients.
3- Document Colloboration
In previous releases of Exchange, OWA included document preview for Office and PDF documents, reducing the need to have a full fidelity client. SharePoint had a similar feature, however it used the Office Web Apps Server to accomplish this capability. Within Office 365, we also leverage Office Web Apps Server to provide this capability, ensuring uniform document preview and editing capability across the suite.
In Exchange Server 2016, we leverage Office Web Apps Server to provide the rich document preview and editing capabilities for OWA. While this was a necessary change to ensure a homogenous experience across the Office Server suite, this does introduce additional complexity for environments that don’t have Office Web Apps Server.
4- Outlook Connectivity
Introduced in Exchange Server 2013 Service Pack 1, MAPI/HTTP is the new standard in connectivity for Outlook. In Exchange Server 2016, MAPI/HTTP is enabled by default. In addition, Exchange Server 2016 introduces per-user control over this connectivity model, as well as, the ability to control whether the protocol (and Outlook Anywhere) is advertised to external clients.
Exchange Server 2016 will only be supported on Windows Server 2012 R2 and Windows Server “10” operating systems.
From an Active Directory perspective, Exchange Server 2016 will require:
- Windows Server 2008 R2 or later Active Directory servers.
- Windows Server 2008 R2 or higher Forest Functional Mode and Domain Functional Mode.
Exchange Server 2016 will only support coexistence with Exchange Server 2010 SP3 RU11* and Exchange Server 2013 CU11* (*subject to change).
These are the main improvements and enhancements that exist in the new version of Exchange