Purpose

This session plan is triggered on receipt of third party REGISTER Request.

Feature Endpoint API

sentinel-sip-spi (SentinelSipMultiLegFeatureEndpoint)

The following diagram is a visual representation of the session plan. It shows:

  • the points-in-session where Sentinel will search for a feature execution script to run (the green boxes)

  • the most important points where Sentinel will make a decision about how the session should be processed further (the grey diamonds)

The session plan is multi-leg aware; for example, within a multi-leg communication session, some of the feature script execution points may be run within the context of a particular ‘leg’. The points-in-session for this session plan are described in detail below the diagram.

sip third party register session plan
Figure 1. Session Plan for a Third Party REGISTER request

Feature script execution points

Below are details of these points-in-session:

Note

The feature endpoint for all sip execution points is SentinelSipMultiLegFeatureEndpoint

On initial trigger …​

The two major tasks Sentinel does on the first message of a new session (the initial trigger) are:

  • decide if the new session can be accepted for processing

  • if the new session is accepted, analyse the initial trigger and classify the session

Should the session be accepted?

Point in session Execution point name Trigger object Trigger activity

Session Accept

SipRegistration_Accept

SIP REGISTER

SipSession

Session Start

SipRegistration_Start

SIP REGISTER

SipSession

Suggested role/purpose of features that run at this feature script execution point

Features that run at this execution point analyse the incoming third party REGISTER request and extract the embedded 1st party REGISTER request and response. Properties of the request can also be used to determine the network operator.

…​ analyse the initial trigger …​

Point in Session Execution point name Trigger Object Trigger Activity

Network Check

SipRegistration_NetworkCheck

SIP REGISTER

SipSession

Session Check

SipRegistration_SessionCheck

SIP REGISTER

SipSession

Subscriber Check

SipRegistration_SubscriberCheck

SIP REGISTER

SipSession

Suggested role/purpose of features that run at this feature script execution point

Features that run at these execution points should analyse the 1st party REGISTER request and response to classify this session. For example features should extract public and private identities and determine type of registrartion scenario (register vs re-register vs de-register).

The three execution points allow you to select feature execution scripts in phases, as you further classify details of the session. For example: the first execution point can select a feature execution script that is particular to the network operator; the next execution point can select a feature execution script that is particular to the session type; and the last execution point can select a feature execution script that is particular to the plan and subscription ids.

…​ on an out-of-dialog SIP transaction response …​

Point in session Execution point name Trigger object Trigger activity

Transaction Response

SipTransaction_Response

SipResponse

SipSession

Suggested role/purpose of features that run at this feature script execution point

Features that run at these execution points should decide what will happen to this leg, its usages, and the multi-leg session, as the leg proceeds.

…​ …​ as each leg ends

Point in session Execution point name Trigger object Trigger activity

Leg End

SipLegEnd

LegEndEvent

SipSession

Suggested role/purpose of features that run at this feature script execution point

Features that run at this execution point should decide what will happen as the leg ends.

Ending the session …​

A session may end for many reasons (a subscriber hangs up a call, there is no credit and so on).

…​ on session end

Point in Session Execution Point Name Trigger Object Trigger Activity

End Session

SipEndSession

EndSessionEvent

SipSession

Suggested role/purpose of features that run at this feature script execution point

Features that run at this execution point may inject behaviour, such as sending notifications, when a session ends.

At any time …​

There are a number of feature script execution points that may be triggered at ant time within the lifetime of a session.

As timers expire

Point in Session Execution Point Name Trigger Object Trigger Activity

Service Timer

SipAccess_ServiceTimer

TimerEvent

NullActivity

Suggested role/purpose of features that run at this feature script execution point

Service timers that are not configured to invoke a feature directly trigger this feature script execution point. Features that run at this execution point should decide what will happen to this session when the service timer expires.

Tip See Sentinel Service Timer Provider for more details.

If instruction execution fails

Point in Session Execution Point Name Trigger Object Trigger Activity

Instruction Execution Failure

SipInstructionExecutionFailure

InstructionExecutionFailedEvent

SipSession

Suggested role/purpose of features that run at this feature script execution point

Features that run at this execution point should decide what will happen to this session when a Leg or Charging Manager instruction failed to execute successfully.

As extension events are processed

Point in Session Execution Point Name Trigger Object Trigger Activity

Feature Extension Event

SipAccess_FeatureExtentionEvent

Object

Extension Activity

Suggested role/purpose of features that run at this feature script execution point

Features that are invoked directly by Sentinel run in the context of the this feature script execution point.

Tip See Sentinel Feature Extension Events and Sentinel Service Timer Provider to learn how a feature can be invoked directly.
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