A Survivable Core Server (SCS), formerly known as Enterprise Survivable Processor, provides geo-redundant Communication Manager Feature Server redundancy. It supports multiple Data Centers for a failed or unreachable main Communication Manager. Session Manager works with the SCS as follows:
After the main Communication Manager goes down, Session Manager starts sending SIP messages to the SCS.
When the main Communication Manager recovers, Session Manager again starts sending SIP messages to the main Communication Manager instead of the SCS.
