Avaya G250 Maintenance Manual page 76

Avaya Communication Manager controlled maintenance
Call features (such as Hold, Transfer, and Drop) are unavailable on preserved connections.
Users attempting to invoke any of the call features receive denial treatment. Callers can make
new calls, but only after hanging up from an old call.
Connection Preservation does not preserve:
Calls on hold or listening to announcements or music (not considered stable calls)
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ISDN BRI calls
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IP trunk calls (SIP, H.323)
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Calls on hold (soft or hard)
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Calls with dial tone
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Calls in the ringing state
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Calls in the dialing state
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Calls in vector processing
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Calls in ACD queues
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Calls on port networks that failover or failback
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If the G250/G350 re-registers with the primary MGC before the Link Loss Delay Timer expires,
the primary MGC fully preserves the calls that it is already aware of and reconstructs only those
calls that the new MGC started. If the G250/G350 re-registers with the primary MGC after the
Link Loss Delay Timer expires, then the G250/G350 reconstructs calls, since the primary MGC
has no knowledge of the calls.
Note:
In an ISDN NFAS scenario, media gateways with D-Channels migrate to the new
Note:
MGC while the B-Channels might remain at the same MGC. The new MGC does
not drop the B-Channels on active (stable) calls in response to D-Channel going
out of service.
VoIP monitoring
The VoIP monitoring mechanism is based on the assumption that RTCP is enabled on all
endpoints and that the media gateway should receive RTCP/RTP packets for all the ephemeral
terminations that are in the active context at the time of call setup. The channel is released if
there is no VoIP activity on the channel, freeing these resources.
The VoIP engine detects VoIP activity using the following criteria:
Detection on the channel is enabled only if the far end has sent at least one RTCP packet
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during the call
The VoIP engine declares a channel inactive when:
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- The channel has received RTCP packets at some point, AND
- No new RTCP packets are received for 150 seconds, AND
- No RTP packets are received during the same time interval
76 Maintenance for the Avaya G250 and Avaya G350 Media Gateways