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Cisco Unified Survivable Remote Site Voicemail




Cisco Unified SRSV-CUE


Cisco Unified Survivable Remote Site Voicemail (Cisco Unified SRSV) is an application that adds support for a survivability architecture to Cisco Unity Connection voicemail solutions. It works with the various Cisco Unity Connection components to provide an enhanced user experience in the branch office. It is a system, made up of a central office and one or more branch offices, that provides voicemail services during a WAN outage.


When a remote site does not have access to your central voicemail system, for example during a network service interruption, Cisco Unified SRSV provides voicemail backup services to help ensure your remote site continues to have voicemail service. This solution also provides Automated-Attendant or call-handler services while in survivability mode.


Components in SRSV Solution


In order to deploy Cisco Unified SRSV solution, you need to deploy the following components:

  • Cisco Unified Communications Manager as the central call control agent
  • Unity Connection as Voicemail server
  • The Cisco Unified Messaging Gateway (UMG-SRSV) in the headquarter as provisioning agent
  • CME-as-SRST running as call control agent during failover mode on branch offices
  • The Cisco Unified Survivable Remote Site Voicemail—Cisco Unity Express (Cisco Unified SRSV-CUE) running on the same router as SRST to provide voicemail survivability.

Survivable Remote Site Voicemail Deployment




Cisco SRSV solution with the help of the application (UMG-SRSV) running on Cisco Unified Messaging Gateway platform automatically synchronize the remote office subscribers’ information from Cisco Unified Communications Manager and Cisco Unity Connection.


After that the Cisco Unified Messaging Gateway provisions the remote branch offices over the WAN link. In remote offices, Cisco Integrated Service Routers (ISR and ISR G2) will enable survivable telephony service to act as a call control agent during the failover operation, meantime, a Cisco Unity Express (CUE-SRSV) is installed on the same router to provide the voicemail and basic auto attendant service during the failover mode.


SRSV uses bandwidth from the WAN link during the following activities:

Configuration uploads from Unified CM and Cisco Unity Connection to Cisco Unity Express SRSV

Voice message uploads from Cisco Unity Express SRSV to Cisco Unity Connection when the WAN link is restored


To minimize the impact of SRSV traffic on the existing voice network, classify the SRSV traffic (configuration and voice message uploads) as best-effort. The SRSV software does not mark any network packets. Cisco recommends marking the SRSV traffic with IP Precedence 0 (DSCP 0 or PHB BE) in the network edge router in order to yield to voice and other high-priority traffic. To further reduce the impact, Cisco recommends scheduling the configuration uploads to take place during non-peak hours (for example, in the evening hours or during the weekend). The schedule can be configured from the Unified Messaging Gateway SRSV web interface.


When you deploy SRSV, the following rules apply:

Unified Messaging Gateway SRSV supports up to 1,000 Cisco Unity Express SRSV nodes.

SRSV does not support Cisco Unified CM Business Edition.

Install Cisco Unity Express SRSV on the SRST router or on Unified CME running in SRST mode.

Multiple SRST routers are supported in the branch, but each router must have its own Cisco Unity Express SRSV and allows only one Cisco Unity Express SRSV.

Deploy redundant Unified Messaging Gateway SRSV to provide high availability for voice message uploads. Unified Messaging Gateway SRSV does not support high availability for configuration uploads.

Use Secure Socket Layer (SSL) protocol to secure the connection between Unified Messaging Gateway SRSV and Cisco Unity Express SRSV.

SRSV does not support Cisco Unity.

For more information on SRSV, refer to the documentation available at

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