WAN requirements betwen Unity and Exchange servers

Unanswered Question

I was looking for some hardened WAN performance requirements of when the Unity server (5.0) is at a remote office from the Exchange (2007) server in a Unified Messaging environment. I haven't been successful finding anything in the SRND section or elsehwere. Can anyine speak to this? THANKS, Mike.

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gpulos Tue, 05/13/2008 - 06:45

There are issues such as number of subscribers, size of mailboxes, UM or VM only configuration, etc. that will be part of dictating your WAN requirements.

Get that info lined up and then see the following link for Exchange UM Planning requirement info:


Tommer Catlin Tue, 05/13/2008 - 09:08

typically, Cisco recommends Unity and Exchange be located at the same location. The reason being, Unity needs to have a constant connection to the information store for turning on/off MWI lights. Unity could miss a MWI easily if the WAN is dropping packets, or latency is an issue. I believe in the SRND, there is some information about Unity Architecture. If not this book I know has it.



Tray Stoutmeyer Tue, 05/13/2008 - 18:35

If you look at the Unity 5.x design guide you will see the recommendation is to have Unity and Exchange at the same site.

Here is the link.


Here is the excerpt from the pdf off this link above.

To ensure that Cisco Unity functions properly, we require that a Cisco Unity server be in the same data center as the following servers:

•The Exchange server that Cisco Unity communicates with, commonly known as the partner Exchange server. For more information on the partner Exchange server, see the “Exchange Considerations (All Versions)” section on page 4-13.

•Every Exchange server on which mailboxes for that Cisco Unity server are homed. If Cisco Unity is separated by a WAN from an Exchange server on which subscriber mailboxes are homed, a second Cisco Unity server must be co-located with the remote Exchange server.

•At least one domain controller. If Cisco Unity subscribers are homed in more than one domain, a DC for each domain must be in the same data center as the Cisco Unity server.

•At least one global catalog server.

•At least one DNS server.

There is more in the pdf but you can check it out on your own.

Good luck!



That's good stuff- thanks. My problem with these general statements that I keep coming across in documentation is that there are routed WAN/MAN links being provided by carriers that are 100M, even a Gig. Some solid specifications speaking to bandwidth, latency, etc would be nice to see from the developers/engineers rather than some "should be on the same LAN" cop-out.

This info is probably the best I'll get- thanks!


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