The following key points were discussed in this chapter:
- MGCP fallback works in conjunction with SRST to provide telephony service to remote IP Phones during WAN failure.
- Making the Cisco IP Phone CUCM list shorter results in faster SRST switchover.
- The Cisco Unified SRST version is linked with the Cisco IOS Software release.
- The MGCP gateway fallback default application is H.323 or SIP.
- When SRST is active, several measures must be taken to ensure connectivity from remote sites to PSTN destinations, between different sites, and inside the site itself.