Corporate users who migrate to Exchange 2007 will face mandatory infrastructure changes that, while advancing security and management, could add complexity and costs to their networks.
The major changes beyond the 64-bit-only platform include a new role-based architecture that has the potential to require users to roll out up to five types of Exchange servers to support functions such as remote client access, transport/routing, mailboxes and unified messaging. The current versions of Exchange give users two deployment options, front-end servers and back-end servers.
Users also will face new clustering limitations and will have to eliminate all Exchange 5.5 servers from their environments. In addition, they will not be able to do in-place upgrades between Exchange 2000/2003 and Exchange 2007. And Exchange no longer will have its own site topology but will run on top of Active Directory topology.
In addition, Microsoft has yet to release detailed migration and best practices guidelines to users. The first public beta of Exchange 2007 is due by the end of July.
"More complex, yes," a network consultant for WM-Data in Sweden, Peter Exstrop, said. "Before, all the roles were on the same server, but now you will have more servers."
While Exstrop acknowledged that nearly all the Exchange 2007 roles can be deployed on one server, for larger deployments that will not be a viable option.
"But I look forward to splitting the server roles," he said. "Security is better, you don't have to have a complete Exchange server in your DMZ to receive mail." With earlier versions of Exchange, those servers in the DMZ were viewed as a security risk.
Another major area of change will be clustering. Users will only be able to cluster servers deployed in the mailbox role. And edge servers, which can supply email hygiene services such as anti-virus/spam protection, will be required to run on a dedicated server and with Active Directory Application Mode.
"We had our routing [service] on a cluster and now it needs to go somewhere else, and that means more servers," applications analyst for the law firm of Katten Muchin and Rosemann, Christopher Wenzel, said.
Wenzel, who has clusters running in four of his five Exchange sites around the United States, noted that best practice guidance from Microsoft for Exchange 2003 was to cluster servers.
"In the past, the idea was server consolidation, but not anymore," he said. "Now it is scaling out again. My footprint increases in that I need more servers and more money for licensing [Exchange and Windows]."
Microsoft has yet to release licensing option requirements for Exchange 2007.
He also said the new Clustered Continuous Replication, which allows for geographically dispersed "clusters" and prevents against site failures, may be more than he wants: "Most of my outages are not site failures. I don't want Exchange to fail over from Los Angeles to Chicago."
But Wenzel said the need for unified messaging, a major new feature of Exchange 2007, was driving his upgrade plan along with improvements in Outlook Web Access and search.
"We have never been afraid of upgrades. If they add to the productivity of our attorneys then we think it is worth it," he said.
Microsoft is expected to introduce enough infrastructure changes that experts say users with multi-site, multi-server Exchange installations must carefully plan their Exchange 2007 architectures.
"Users have to re-think the infrastructure stuff with front-end and back-end servers," an analyst with Directions on Microsoft, Peter Pawlak, said. "Now it is all about client-access servers, mailbox servers, transport servers and unified messaging."
Pawlak said the results of the changes should be a positive for users, including tying Exchange to the Active Directory site structure.
"If the Active Directory site is designed correctly, this should make Exchange administration easier," Pawlak said. "Administrators no longer have two site structures to design."
The Exchange/Active Directory match isn't the only dependency in Exchange 2007.
Users will have to have at least one client-access server and one hub server in each site that contains a mailbox server. Those roles, however, can run together on the same server. And both those servers will have to be Exchange 2007 servers in order to support Exchange 2007's revamped Outlook Web Access client.
Users also might find that 32-bit third-party plug-ins to Exchange, especially those that run on the server, may not run properly.
"Many of the 32-bit applications will run," corporate vice-president of the Exchange group at Microsoft, Dave Thompson, said. "But they will have to be considered on a case-by-base basis. The ones that won't [run on 32-bit] will need a compatibility kit."
For unified messaging, users will have to integrate Exchange with a PBX, and Microsoft has yet to detail the technical aspects of that union.
"It is not trivial connecting a PBX to Exchange, and people will not [change] out their PBX for this product," Pawlak said.