Standard Local Survivability (SLS) provides a local Branch Gateway with a limited subset of MGC functionality when there is no IP-routed WAN link available to an MGC, or no MGC is available.

SLS is supported on IPv4 only.

SLS is not a replacement for ELS or SRS (Survivable Remote Server) survivability, which offer full call-feature functionality and full translations in the survivable mode. Instead, SLS is a cost-effective survivability alternative offering limited call processing in survivable mode. Although the Branch Gateway can host an S8300 Server in ICC or SRS mode, SLS offers both local survivability and call control.

In contrast to the server-based survivability features, SLS operates entirely from the Branch Gateway and requires a data set comprised of CM translations (survivable ARS analysis and configuration data). This data set can be configured manually from individual Branch Gateways using CLI commands. For instructions on configuring SLS, see SLS configuration rules.