ESRVCC registration process

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ESRVCC registration process (Click image to enlarge)

ATCF not involved in registration

The ESRVCC registration feature takes no further action and ends.

ATCF is involved in registration

  • The Feature-Caps header of the first-party REGISTER request includes a number of ATCF-related parameters:

    • +g.3gpp.atcf

    • +g.3gpp.atcf-mgmt

    • +g.3gpp.atcf-path

  • The ESRVCC registration feature:

    • queries the HSS to obtain the STN-SR and the C-MSISDN (correlation MSISDN)

    • compares the STN-SR returned by the HSS with the STN-SR that was in the first-party REGISTER request

      • If they are different, the HSS is updated with the STN-SR from the first-party REGISTER request

    • updates the ATCF, passing it the SCC AS’s own ATU-STI and the C-MSISDN, by sending the ATCF a SIP MESSAGE message.

      • The address of the ATCF is taken from the +g.3gpp.atcf-mgmt parameter in the Feature-Caps header of the first-party REGISTER request.

      • The body of the SIP MESSAGE has a content type application/vnd.3gpp.SRVCC-info+xml and contains an XML document such as:

        <?xml version="1.0" encoding="UTF-8"?>
<SRVCC-infos>
    <SRVCC-info ATCF-Path-URI="<sip:termsdgfdfwe@localhost:5560>">
        <ATU-STI>sip:sccas1.home1.net:5060</ATU-STI>
        <C-MSISDN>tel:+16505550425</C-MSISDN>
    </SRVCC-info>
</SRVCC-infos>
Note If any of these steps fail (for example, the ATCF update times out, or the HSS returns a failed Answer) the ESRVCC registration feature responds to the registrar core with rejectRegisterRequest().

Prerequisite features

Session state

Before …​

SentinelSelectionKey

A selection key with the platform operator, network operator and session type set to ESRVCCRegistration (such as OpenCloud:OpenCloud:ESRVCCRegistration::)

EncapsulatedRegisterRequest

The first-party REGISTER request that was in the body of the third-party REGISTER request received by the registrar. The ESRVCC feature processes the Feature-Caps header from the REGISTER request.

…​ After

CorrelationMsisdn

The correlation MSISDN retrieved from the HSS

StnSR

The STN-SR from the third-party register request, if it differs from the current HSS state.

Mappers

This feature uses mappers that conform to:

Mapping Mapper Execution Point

SentinelRegistrarSessionState.class → OutgoingSipRequest.class

RegistrarMappingPoint.UpdateATCF

Feature responses

None

Statistics

ESRVCCRegistration statistics are tracked by the sentinel.registrar SBB and can be found under the following parameter set in REM:
SLEE-Usage → sentinel.registrar service → sentinel.volte.sip SBB → feature → CacheESRVCCRegistration
or with rhino-stats:
"SLEE-Usage.Services.ServiceID[name=sentinel.registrar,vendor=OpenCloud,version=2.9.0].SbbID[name=sentinel.registrar,vendor=OpenCloud,version=2.9.0].feature.CacheESRVCCRegistration"

Parameter …​ incremented if …​

Started

The feature runs

FailedToStart

A fatal error occurs before feature execution

IssuedWarning

A non-fatal error occurs during feature execution

FailedDuringExecution

A fatal error occurs during feature execution

TimedOut

Feature execution does not complete within a reasonable time frame

MapperErrorSendingPUR

The mapper that creates a ProfileUpdateRequest fails

NetworkErrorSendingPUR

There is a network error sending a ProfileUpdateRequest to the HSS

HssSentErrorPUA

The HSS responded to a ProfileUpdateRequest with an error response

MapperErrorUpdatingATCF

The mapper that creates a SIP MESSAGE message, to pass to the ATCF, fails

NetworkErrorUpdatingATCF

There is a network error sending a SIP MESSAGE message to the ATCF

ATCFRespondsWithSipError

The ATCF responds to a SIP MESSAGE message with an error response

ATCFResponseTimesOut

There is no response to the SIP MESSAGE message sent to the ATCF

RegisterMissingFeatureCAPSHeader

The REGISTER message is missing a Feature-Caps header

RegisterFeatureCAPSHeaderMissingAtcfMgmt

The Feature-Caps header does not contain a +g.3gpp.atcf-mgmt parameter

Error scenarios

The ESRVCC feature increments statistics and responds to the registrar core with rejectReqisterRequest() if:

  • the REGISTER request is missing essential headers or header parameters

  • there is a problem sending a UserDataRequest to the HSS, such as a mapper error creating the message, or a network error sending the message

  • there is a problem sending a ProfileUpdateRequest to the HSS, such as a mapper error creating the message, or a network error sending the message

  • there is a problem sending a SIP MESSAGE message to the ATCF, such as a mapper error creating the message, or a network error sending the message.

Configuration

This feature has a configuration profile which determines the user identities used when querying the HSS. The default profile table is named CacheESRVCCRegistrationConfigProfileTable and profiles are named with a Sentinel Selection Key e.g. opencloud::::. The feature has a Sentinel Feature Configuration page in REM.

Attribute Name Type Description

UserIdentityTypeStringForStnSrRequest

An enum with value PUBLIC_ID or CMSISDN

Determines whether the user’s IMS Public ID or C-MSISDN will be used for their identity when requesting the STN-SR from the HSS.

IncludePrivateIdInStnSrRequest

boolean

Determines whether the user’s IMS Private ID will be included in the request for the STN-SR.

There are also fields relevant to this feature in the RegistrarConfigurationTable table:

AtcfUpdateTimeout

The time (ms) the ESRVCC registration feature should wait for a response from the ATCF.
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Sentinel VoLTE Version 2.9.0