Topic Last Modified: 2010-07-18
Survivable Branch Appliances and Survivable Branch Servers can provide voicemail survivability for branch users during a WAN outage, if Exchange Unified Messaging (UM) is installed at the central site and an Exchange UM Message Auto Attendant (AA) is deployed. We recommend that your Exchange administrator deploy a Talking Mode AA, which is a special type of AA that disables all other generic functionality, such as transfer to a user or transfer to an operator, and limits the AA to only accept messages. Alternatively, you might use a generic AA or an AA customized to route the call.
For more information, see the “Voice Mail Survivability” section in Branch-Site Voice Resiliency, in the Planning Guide.
To configure voice mail survivability
In the Communications Server Management Shell, use the New-CSVoiceMailReroutingConfiguration cmdlet to set the AA phone number as the Exchange UM Auto Attendant phone number in the voice mail rerouting configuration on the Survivable Branch Appliance or Survivable Branch Server.
Note: If you need to modify the voice mail rerouting setting later, use the Set-CsVoiceMailReRoutingConfiguration cmdlet to do so. For more information, about New- and Set-CSVoiceMailReroutingConfiguration, in the Shell Help topics.
Set the Exchange UM subscriber access number that corresponds to the branch user’s Exchange UM dial plan as the Exchange UM subscriber access number in the voice mail rerouting configuration on the Survivable Branch Appliance or Survivable Branch Server.
Note: Configure the Exchange UM users’ dial plan so that there is only one dial plan associated with all branch users who need access to the Get Voice Mail functionality during a WAN outage.
Next step for Survivable Branch Appliances or Servers: Home Users on a Survivable Branch Appliance or Server