Cisco UCM failure scenarios for passive recording

This topic describes the most common Cisco Unified Communications Manager failure scenarios that may impact the passive call recording service. Verba has many built-in features to handle and provide survivability of the system for Cisco Unified Communications Manager failure scenarios.

Timeout

A global parameter defines the timeout value for each Verba system (the default value of this parameter is set to 300 seconds, 5 minutes). If the last received RTP packet of a call/session is older then the timeout value, Verba terminates that recording session. The timeout check is performed in every minute.

When a call has to be terminated, because its last RTP packet is too old, Verba closes the media file at the last received RTP packet and updates the metadata with the proper termination time value (equals to the last RTP packet time). The termination cause value for this call is set to "Timeout" (80).

If the telephony system uses silence suppression then it is possible that none of the calling parties talk for a long period. If the silence takes longer than the timeout value, Verba will terminate this type of call too. In order to avoid this situation; you have to set the timeout value greater in the configuration.

Forced termination

When Verba identifies that a call has started between two IP phones, it terminates all recording sessions forcefully that belong to any of the given IP phones.

This feature enables the system to immediately recognize Unified Communications Manager failure. If an IP phone starts a call, it means that older calls for this station are no longer alive (there was a Unified Communications Manager failure during the previous call).

When a call has to be forcefully terminated, because of a new call start, then Verba closes the media file at the last received RTP packet and updates meta data with the proper termination time value (equals to the last RTP packet time) for the given recording session. The termination cause value for this call is set to "Forced termination" (81).

Single Unified Communications Manager server

This scenario is only applicable, when one Unified Communications Manager is deployed. If the Unified Communications Manager fails, the ongoing calls continue without interruption. Verba is able to record these calls and terminate the recording sessions properly using the following features:

  • Initially, calls are terminated by Verba, with reason code 80.
  • If the same parties start a new call (after Unified Communications Manager becomes available), previous calls are forcefully terminated by Verba, applying reason code 81.
  • When Unified Communications Manager resumes its operation normally, every new call is handled as usual.

Multiple Unified Communications Manager servers

This scenario applies, when more than one Unified Communications Manager server is deployed. If the active Unified Communications Manager fails, the ongoing calls continue without interruption. Verba is able to record these calls and terminate the recording sessions properly using the following features:

  • Initially, calls are terminated by Verba, using reason code 80.
  • If the same parties start a new call, previous calls are forcefully terminated by Verba, applying reason code 81.
  • When the standby Unified Communications Manager server becomes active and the IP phones register in, all of the new calls are handled as usual.

SRST scenario

This scenario applies, when an SRST gateway is deployed at a remote site. If the WAN link fails, the ongoing calls continue without interruption. The Verba Recording Server is able to record these calls and terminate the recording sessions properly using the following features:

  • Initially, calls are terminated by Verba applying reason code 80.
  • If the same parties start a new call (after registering with the SRST router), previous calls are forcefully terminated by Verba, applying reason code 81.
  • When the SRST service becomes active and the IP phones registers with it, all of the new calls are handled as usual.

IP phone failure

When an IP phone fails (e.g. network connection is broken), ongoing calls are interrupted for the given IP phone. Verba is able to terminate the recording sessions properly using the following features:

  • Initially, calls are terminated by Verba applying reason code 80.
  • If the same parties start a new call (after IP phone connection becomes available), previous calls are forcefully terminated by Verba, applying reason code 80.
  • When the IP phone becomes active, all of the new calls are handled as usual.