To improve the product’s capabilities and simplify the architecture and its deployment, MS have removed the Client Access server (CAS) role and added the client access services to the Mailbox role.
The Mailbox server role now:
1. Knows the logic to route emails
2. Hosts all the components/protocols for exchange services
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.
We still have DAG for high availability with the below improvements
1. By default, the failover cluster will be created without an administrative access point,
2. Replay Lag Manager is enabled by default.
3. Database failovers times are reduced by 33% when compared to Exchange Server 2013.
How outlook connects to the Mailbox server
1. A client resolves the namespace to a load balanced virtual IP address.
2. The load balancer assigns the session to a Mailbox server in the load balanced pool.
3. The Mailbox server authenticates the request and performs a service discovery by accessing Active Directory to retrieve the following information:
a. Mailbox version (for this discussion, we will assume an Exchange 2016 mailbox)
b. Mailbox location information (e.g., database information, ExternalURL values, etc.)
4. 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).
5. The Mailbox server queries an Active Manager instance that is responsible for the database to determine which Mailbox server is hosting the active copy.
6. The Mailbox server proxies the request to the Mailbox server hosting the active copy.
Coexistence with Exchange Server 2013
In Exchange Server 2013, the Client Access server role is simply an intelligent proxy that performs no processing/rendering of the content. That architectural tenet paid off in terms of forward coexistence. When you introduce Exchange Server 2016, you do not need to move the namespace. That’s right, the Exchange Server 2013 Client Access infrastructure can proxy the mailbox requests to the Exchange 2016 servers hosting the active database copy! For the first time ever, you get to decide when you move the namespace over to the new version. And not only that, you can even have load balancer pools contain a mix of Exchange Server 2013 and Exchange Server 2016. This means you can do a one-for-one swap in the load balancer pool – as you add Exchange 2016 servers, you can remove Exchange 2013 servers.
Topology Requirements
Exchange Server 2016 will only be supported on Windows Server 2012, Windows Server 2012 R2 and Windows Server “10” operating systems.
From an Active Directory perspective, Exchange Server 2016 will require:
- Windows Server 2008 or later Active Directory servers.
- Windows Server 2008 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).
No comments:
Post a Comment