AudioCodes Mediant 8000, Инструкция по установке, эксплуатации и обслуживанию

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Installation & Operation Manual 812 Document # LTRT-92224
Mediant 8000
46.1.1 Hitless Upgrade Mode
Starting from Version 6.2, Hitless Upgrade mode is supported for the upgrade of
Media Gateway boards. In this mode, activity switchover is performed between
Normal and Redundant Media Gateway boards. As a consequence, established calls
are not affected during the Media Gateway boards upgrade. Calls that have not been
established may be dropped.
Although Hitless Upgrade Mode is the preferred upgrade mode, it may be not
available due to one of the following reasons:

Redundant Media Gateway board is not available or out of service during the
upgrade;

Configuration of the specific Media Gateway board doesn't allow hot
redundancy;

New software doesn't support Hitless Upgrade mode for specific current software
version;
In all above cases, Graceful Shutdown mode will be used for upgrading affected
Media Gateway boards. For more information, see Section 'Graceful Shutdown Mode'
on page
812 .
46.1.2 Graceful Shutdown Mode
Graceful Shutdown mode is available for all Media Gateway boards' without any
dependency on the Redundant Media Gateway board's availability or any specific
configuration. In this mode, each Media Gateway board is upgraded after a definable
Graceful Shutdown period. During this period, no new calls are established on the
Media Gateway board; however, the remaining active calls are allowed to complete
normally. The Graceful Shutdown period ends when either there are no more active
calls on the Media Gateway board, or the defined time period ends. If the defined time
period ends and there are still active calls, these calls are dropped and the Media
Gateway board is restarted.
The Graceful Shutdown period helps to ensure that a negligible number of calls are
dropped during a Media Gateway board's upgrade. In any case, the Media Gateway
capacity is never reduced by more than a single Media Gateway board's capacity. To
further minimize the effect of a Media Gateway board upgrade, it is recommended that
you distribute customer trunks across at least two different Media Gateway boards.
Note:
To further minimize call traffic loss during the Media Gateway boards'
upgrade, perform this procedure when low call traffic is known to occur.