Cisco Survivable Remote Site Telephony - Licence - modems

Cisco Survivable Remote Site Telephony (SRST) is a feature in Cisco Unified Communications Manager that provides call processing redundancy at remote branch office locations in case of a WAN failure.

The purpose of using Cisco SRST is to ensure business continuity by allowing remote branch offices to continue making and receiving calls even if they lose connectivity to the central Unified Communications Manager.

The licence for SRST modems by Cisco Systems includes the necessary software licensing to enable the SRST feature on supported Cisco devices.

Modems are not required for Cisco SRST, but an appropriate licence may be needed depending on the specific deployment and device configurations.

During a WAN failure, SRST enables the on-site router to take over call processing tasks, such as call routing and call setup, ensuring that voice communication can still function locally.

Yes, users at a branch office with Cisco SRST configured can still make internal calls within the branch office or to other branches that are also running SRST or have direct communications set up.

Additional hardware such as supported routers and switches may be required to implement Cisco SRST in a network environment, in addition to the necessary software licences.

Cisco SRST supports basic call processing features such as making and receiving calls, voicemail, call transfer, and conferencing. However, some advanced Unified Communications features may not be fully supported in SRST mode.

Cisco SRST can be deployed and configured through the Cisco Unified Communications Manager administration interface by specifying the branch office locations that require SRST support and assigning the appropriate licence and settings.

The number of IP phones that can be supported by Cisco SRST depends on factors such as router capacity and available resources, but typically several hundred IP phones can be supported in an SRST deployment.