5.1 Introduction – Implementing SRST and MGCP Fallback

Cisco Unified Communications Manager multisite deployments with centralized call processing are simple to implement. The possibility to have multiple servers in a cluster provides redundancy of the centralized services.

However, in some situations, IP connectivity between remote sites and the central site is broken and none of the centralized servers are reachable. Cisco Unified Communications Manager offers survivability features to remote sites even in such scenarios.

In this section, we describe how to implement Cisco Unified SRST on Cisco IOS routers in order to provide redundancy to IP phones. We also describe how to configure the MGCP gateway fallback feature.