Communication Manager supports a wide range of servers, gateways, and survivability features, enabling maximum availability for customers. The software can mirror processor functions, provide alternate gatekeepers, support multiple network interfaces, and ensure survivability at remote and central locations.

The reliability feature includes:

• Alternate gatekeeper: Provides survivability between Communication Manager and IP communications devices such as IP telephones and IP softphones.

• Auto fallback to primary for Branch Gateway: Automatically returns a fragmented network, where several Branch Gateways are serviced by one or more Communication Manager Survivable Remote sites to the primary server. This feature is targeted for Branch Gateways.

• Connection preserving failover/failback for Branch Gateway: Preserves existing bearer or voice connections while Branch Gateways migrate from one Communication Manager server to another. A network or server failure can cause the existing bearer or voice connections on the Branch Gateway to move to another Communication Manager server.

• Connection preserving upgrades for duplex servers: Provides connection preservation on upgrades of duplex servers for:

  • Connections involving IP telephones

  • Connections on Branch Gateway

• Communication Manager Survivable Core: Provides survivability for backup servers to be placed in various locations in the customer network.

  • When the Survivable Core is in control due to a network fragmentation or catastrophic main server failure, the return to the main server is automatic. It is provided by the scheduled, manual, and automatic options.

  • Dial Plan Transparency for Survivable Remote and Survivable Core preserves dialing patterns of users if a Branch Gateway registers with Survivable Remote.

• IP endpoint Time-to-Service: Improves a customer’s IP endpoint time to service, especially where the Communication Manager has many IP endpoints trying to register or re-register. With this feature, the system considers that IP endpoints are in-service immediately after registering. The feature of TTS-TLS supports TTS over a secure TLS connection. This is the Avaya recommended configuration choice.

• Survivable processor: A survivable processor is an Internal Call Controller (ICC) with an integral Branch Gateway. The ICC is administered to function as a spare processor rather than the main processor. The standby Avaya Solutions Platform S8300 Server runs in standby mode, with the main server ready to take control in an outage with no loss of communication.

• Handling of split registrations: Occurs when resources on one network region are registered to different servers. For example, after an outage activates the Survivable Remote server (Local Survivable Processors) or Survivable Core server (Enterprise Survivable Server), telephones in a network region register to the main server, while the Branch Gateways in that network region are registered with the Survivable Remote server. The telephones registered with the main server are isolated from their trunk resources. Communication Manager detects a split registration and moves telephones to a server with trunk resources.

• Power failure transfer: Provides service to and from the local telephone company central office (CO), including a wide-area telecommunications system, during a power failure. With this feature, you can make or answer important or emergency calls during a power failure. This feature is also called emergency transfer.

• SRTP for video call flows: This support is available only when the call-originating and the receiving endpoints are SIP-registered, and the IP-codec-set administration on Communication Manager is SRTP. SRTP for video does not work for H.323 signaling. H.323-registered endpoints always send video RTP. SIP-H.323 interworking with video encryption is not supported, and video is blocked in this case. However, if the SIP signaling follows the Best effort SRTP mode, video RTP can pass through in SIP to H.323 interworking in Communication Manager.