The B2BUA Subscription Activity Guard feature tracks outstanding subscriptions and invalidates sessions which have not been correctly shut down.

The B2BUA Subscription activity guard feature is used to protect against servers not correctly terminating their subscriptions. For each non-terminating notify that is B2BUAed by Sentinel, this feature starts a timer which fires after the expiration of the notify. If another notify for the same subscription is received, the timer is updated. If a terminating notify is sent, the timer is cleared and removed. If the timer fires, this shows that a terminating notify has not been sent by the server. In this case, the feature invalidates and detaches from both legs of the call, freeing resources and cleaning up as appropriate.

Details

Feature script name

SubscriptionActivityGuard

Applicable contexts

SIP service

SAS Support

No

Prerequisite features

B2BUA

Requisite Features execution point [script]

SubscriptionSipRequest [Pre]

Timer usage

Feature-targeted timer triggers feature directly on expiry. Does not need to be registered against SipAccess_ServiceTimer execution point.

Session state inputs and outputs

Inputs

Name Type Format Description Behaviour if null/invalid

SentinelSelectionKey

com.opencloud.sentinel.common.SentinelSelectionKey

selection key
for example, <platform>::::

For selecting configuration data

Increment InputParameterErrors Common cleanup actions

Feature responses

Response Reason

featureHasFinished

feature has finished

Statistics

Name Description

ActivityGuardTimeout

Number of times the timer fired and the feature had to terminate the subscription.

B2BUA Subscription Activity Guard configuration

The configuration for the B2BUA Subscription Activity Guard Feature is provisioned in the following table:

Parameter Type Description

ActivityGuardWaitTimeMillis

long

Number of milliseconds to wait after the expiry time before shutting down the legs.

Provisioning interfaces

The feature is provisioned using the Sentinel Features REST API or web interface.

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Sentinel Express Version 4.1