Avaya 9608 - Page 161

Controller Determination and Survivability Activity
Issue 3 January 2014 157
- If the current controller is available and it is the highest priority available controller, the
"Controller Subscription Refresh" function is performed.
- If the current controller is available, but there is a higher priority controller available, the
"Controller Failback" function is performed.
- If the current controller is not available, the "Controller Failover" function is performed.
2. If there is an active call, the controller search (Step 1) is performed when the call is over.
4. AST feature determination
After the Active controller has been selected, the deskphone examines the value of the
DISCOVER_AVAYA_ENVIRONMENT parameter.
If the parameter value is 1, the deskphone determines if that controller supports the AST
(Advanced SIP Telephony) feature set or not. The deskphone sends a SUBSCRIBE request to
the active controller for the "Feature Status Event Package" (avaya-cm-feature-status). If the
request succeeds, the deskphone proceeds with PPM Synchronization. If the request is either
rejected, is proxied back to the deskphone, or does not receive a response, the deskphone
assumes that AST features are not available.
If the parameter value is 0, the deskphone operates in a mode where AST features are not
available.
Upon receiving a 202 Pending response, the deskphone starts an internal timer of 16 seconds
and waits to receive a NOTIFY to determine whether the subscription is active or not. If the
NOTIFY indicates an "active" state, the deskphone considers itself in an AST environment and
proceeds with PPM Synchronization. If the NOTIFY indicates a unreachable state, the
deskphone considers itself in a non-AST environment. It periodically retries the subscription to
the Feature Status Event Package. If it receives a 202 Pending response, it continues as
specified above. If the 16 second timer expires before a NOTIFY is received the deskphone
considers itself in a non-AST environment.
5. Session Manager synchronization
As part of Session Manager synchronization the deskphone performs a
getAllEndpointConfiguration request. This request contains the following
EndpointConfigurationFields:
● VolumeSettings
● LinePreferenceInfo
● ListOfOneTouchDialData
● ListOfButtonAssignments
● SoftMenuKeyList
● DialPlanData
● ListOfSpeedDialData