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New Member

Networking Unity 4.0

I intend to network two unity servers in two different sites linked by a

34MB pipe. The exchange message store however sits on other servers again

split between these two sites.

So my questions are:

1: Would digital networking work in this scenario given all exchange

prerequisites are met? If so, is this a standard feature or extra?

2: Would a proper unity failover work given the above bandwidth?

Cheers ,


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Re: Networking Unity 4.0

What you want to avoid is Unity servicing mailboxes across the link. For example, if you have site a and site b, the Unity server is site b should not service any mailboxes homed on an exchange server in site a. As long as you adhere to that you should be fine. Check out for more information.

All of the networking data is replicated through the directory and cached locally to SQL so link speed really isn't an issue for Digital Networking.

Can you explain what you are trying to do with failover here? It is not supported for failover partners to be separated via a WAN link...



New Member

Re: Networking Unity 4.0


Thanks for your reply. The first paragraph clarifies a whole lot of issues. Well, site B is the disaster recovery (DR) site to site A. Thus the idea has always been to replicate services to the DR site from site A and Unity is to be no exception.

However, exchange is not clustered in this scenario over the WAN which in effect makes failover for Unity even more unthinkable.

So, going by segregating the site mailboxes what happens when site A completely dies? What are the options given all backups are available?




Re: Networking Unity 4.0

I should start by saying that failover was not designed for disaster recovery purposes. It was designed to handle a Unity application failover and nothing more. Since it was designed with that intention only, it was assumed that the Unity servers would be connected to the same 100mbps switch. Low bandwidth situations and WAN links were never considered.

So, if site A died the Unity in site B will run in UMR mode until site A is back online. What you need to be concerned with is what happens if CallManager in site A fails or the Unity server in site A fails. That could get tricky.

Your best bet is to have a Unity server already built (no failover) in the DR location and to do regular backups with DiRT and store them at the DR location as well. If site A goes down for an extended period you can restore from DiRT and contact Cisco to have them move your license to the new MAC address.

Hope this helps,


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