IPCC Redundancy Considerations

Unanswered Question
Oct 16th, 2007

Hi pros,

I need simple answer for IPCC Redundancy. I will install redundant IPCC on two geographic locations. These two locations will have same components like ICM, CVP, PG, Logger, Router etc and these components will work redundant. Also I will use private and visual network lines to communicate the sites.

Here is my question. When my all network lines (visual, private) is crash, can my site A and Site B work alone? I have read the documents and as I understand when all visual and private network gone only one site will work.

Is there anyone has field experience about this. Best regards...

I have this problem too.
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axg85429 Tue, 10/16/2007 - 12:37

You are correct, but under normal circumstances, this should never be the case; that is if your design is fully redundant.

Dennis Fogler Tue, 10/16/2007 - 15:50

Actually yes both sides will work but this is not how UCCE should function. When neither the "visible" or the "private" networks are available, the central controller of UCCE goes into what is called a "split brain" scenario.

In this event each side, both the A & the B side, think they are the primary controller. Each then generates its own recovery key to resync data thinking the other side is down. This event is extremely difficult to recover from and usually requires manual intervention to resync the system.

The whole purpose in having the redundant network paths if so that the central controller can determine A/B side survivability and elect a priamry controller.

When designing the network portion of UCCE definitely pay close attention to the High Availability Section of the UCCE SRND.


Majdi Harb Tue, 10/16/2007 - 19:39


At this point, the Call Router and Unified CM Peripheral Gateway will run in simplex mode, and the

system will accept new calls from only the surviving side for Unified CCE call treatment. The

Unified IP IVR/Unified CVP functionality will also be limited to the surviving side as well.

please see the Scenario 3: Visible and Private Networks Both Fail (Dual Failure) section from





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