Voice Register Global Mode - Srst
Unlike SCCP phones, which register using TCP on port 2000, SIP phones use UDP (typically) on port 5060. The call-manager-fallback service does not natively handle SIP registration logic. The voice register global container is the dedicated engine for SIP provisioning and registration handling.
Or in older MGCP/SCCP SRST configuration: voice register global mode srst
By issuing the mode srst command, the router changes its behavior: Unlike SCCP phones, which register using TCP on