Phone resiliency and transition states
The transition happens in the following order:
1. Limbo: Connection to the primary server is lost but the failover is not detected.
2. Moving Subscriptions Interval (MSI): Connection to the primary server is lost, and the phone
is currently registered to the survivability server. Successful subscription to the survivability
server is incomplete.
3. Acquiring services: Connection to the primary server is lost, and the phone displays the
following message in the idle state
Acquiring Service
4. Failover to the secondary/survivability server: Connection to the secondary/survivability
server is active. All the supported features are also active. The phone performs the following
intermediate steps:
• Selection of active controller: The phone attempts to select the monitored active controller.
• Successful subscription: Connection to the monitored controller is made with successful
subscription.
• Call/media preservation: During an active call, the phone detects that the connection is
lost with the primary controller and the call/media is preserved. Media preservation is only
available in an Avaya Aura
®
environment.
• Advanced SIP Telephony (AST) feature determination: The phone verifies whether the
controller supports the AST feature. AST feature is only available in an Avaya Aura
®
environment.
• Personal Profile Manager (PPM) synchronization: When AST mode is determined and
enabled, then the phone starts the PPM synchronization process. PPM is only available in
an Avaya Aura
®
environment.
5. Failback to the primary server: Connection to the primary server is established when the
phone detects that the primary server is functional again. The changes that were cached
earlier are now synced with the PPM server. Failback does not happen during an active call.
Failover and survivability overview
September 2017
Installing and Administering Avaya J129 IP Phone
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