Polycom 3725-76302-001O manual 24%

MCU Management

●When calls to a specific MCU fail, the RealPresence DMA system reduces the MCU’s reliability score, causing it to be selected less frequently than other MCUs.

An MCU’s reliability depends on the number of consecutive failed calls. As that number increases, the RealPresence DMA system treats a growing percentage of the MCU’s ports as if they were in use. Since the RealPresence DMA system selects the least used of the capable MCUs in its pool, the likelihood that an MCU with failures will be chosen for the next call declines rapidly (depending on the number of consecutive failed calls and the remaining capacity in the MCU pool).

Consecutive	Percentage of Ports
Failed Calls	Assumed To Be in Use
1	24%
2	43%
3	56%
4	67%
5	74%
6	80%
7	84%
8	88%
9	90%

Every 30 minutes, the reliability score of the MCU is increased so that it won’t be permanently removed from the pool due to failures in the distant past. To avoid trying the MCU every 30 minutes, monitor the RealPresence DMA system and administratively take the MCU out of service.

By increasing the number of MCUs in the pool or increasing their capacity, you can decrease the usage of the working MCUs during a failover scenario. So, for example, if you want to avoid routing any more calls to an MCU after two consecutive failed calls, provide enough excess capacity that the remaining MCUs never all reach 43% port usage during a failure.

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