Tip This feature is for CDMA networks.

This feature is triggered from the I-CSCF and retrieves reorigination information. It retrieves the subscriber’s assigned S-CSCF either from an HSS or from a profile from network configuration and then acts as a B2BUA between the I-CSCF and the subscriber’s assigned S-CSCF .

It is one of two components that enable circuit switched originating calls to be processed in the SCC-AS. The related component is the CDMA ReOrigination Service. These components are part of service centralization in the IMS for CDMA networks.

Note For this feature’s fit into the overall flow, please see the Reorigination basic flow diagram.

Relevant specifications

  • 3GPP2 X.S0042-D v1.0

  • GSMA IR.64.

Feature cheat sheet

B2BUA Instance Originating / Terminating Point in Session Plan Network Operator Data Subscriber Data Stateful or Stateless POJO Feature or SBB Feature

SCC signalling anchor B2BUA

From SIP triggering perspective, neither. Mobile Originating and Mobile Terminating determined from saved CDMA OriginationRequest or CDMA AnalyzedInformation

SipAccess_SessionAccept

Yes

No

Stateless

Triggered by the I-CSCF

Network operator data

Common network configuration data is stored in a profile table named SCCCommonReOriginationConfigProfileTable.

For more information, see the shared configuration between the SCCCDMAReOrigination feature and the CDMA reorigination service.

Use of Correlation resource adaptor

For information about use of the Correlation RA, please see the shared Correlation RA.

Session output variables

Variable name Type Comment
Reoriginated

Boolean

Set to true if the feature finds reorigination data

Statistics

SCCCDMAReOrigination statistics are tracked by the sentinel.volte.sip SBB and can be found under the following parameter set:
SLEE-Usage → sentinel.volte.sip service → sentinel.volte.sip SBB → feature → SCCCDMAReOrigination

Statistic Incremented when…​

Complete

The feature ran to completion

MultipleHistoryInfoHeadersFound

Multiple history-info headers found on the INVITE

NoHistoryInfoHeaderFound

No history-info header found on the INVITE

OneHistoryInfoHeaderFoundAndRemoved

One history-info header found on the INVITE and removed

HSSLookupFailed

HSS lookup failed

HSSLookupSuccess

HSS lookup succeeded

HSSLookupSkipped

HSS lookup was skipped due to SkipHSSLookup feature configuration flag

CorrelationRaQueried

Correlation RA was queried for the call information

CorrelationRaQuerySuccess

The Correlation RA query succeeded

CorrelationRaQueryFailure

The Correlation RA query failed

FailedToDecodeCorrelationData

Failed to decode the correlation data into an OriginationRequest or AnalyzedInformation object

SetOCBillingIdHeader

Added a OCBillingId header with the BillingID from the OriginationRequest or AnalyzedInformation

CalledPartyNumberNotFound

Failed to determine the called party from parameters of the OriginationRequest or AnalyzedInformation

SCSCFAddressNotFound

The SCSCF could not be found in configuration, or retrieved from the HSS

CallingPartyAndPaiDoNotMatch

The request is rejected because of a mismatch between calling party and P-Asserted-Identity

CassandraQueried

Cassandra is queried for call information related to a correlation ID

CassandraQueryFailed

There is a failure to execute a cassandra query

CassandraQueryResultReceived

A CassandraQueryResult event is received with the result of the Cassandra query for call information

CassandraQueryErrorReceived

A CassandraQueryError event is received due to a failure

CassandraQueryResultMissingData

A CassandraQueryResult event is received with no call information associated for a correlation ID

CassandraQueryResultExpired

A CassandraQueryResult event is received with call information that has expired

ReleasingCorrelationIdOnRemoteNode

A SIP MESSAGE has been sent to a remote SCC-AS node to release a correlation ID

FailedToReleaseCorrelationIdOnRemoteNode

There was a failure to release a correlation ID on a remote SCC-AS node by sending a SIP MESSAGE

ReleasedCorrelationIdUsedOnRemoteNode

A correlation ID has been released in response to a SIP MESSAGE received from a remote SCC-AS node

Started

The feature starts

FailedToStart

The feature failed to start due to an error

IssuedWarning

The feature raised a warning

FailedDuringExecution

The feature failed due to a major error

TimedOut

The feature timed out during execution

Behaviour

The feature is triggered on receipt of a SIP INVITE from the I-CSCF.

It checks for network operator data. If not present, the feature informs Sentinel that it failed to execute due to invalid configuration.

It looks at the received INVITE Request URI, and checks that it represents a phone number.

If the network configuration indicates a prefix is in use, it checks that the request URI’s digits start with that prefix. If not, the feature finishes execution without modifying any state. In other words, this is treated as an INVITE that is not for this feature.

The feature then attempts to retrieve the correlation data that was stored by the CDMA reorigination service. This data is looked up using the request URI’s digits as the key for the correlation data.

The correlation RA query result includes the call information data if it is available on this SCC-AS node. If the call information is not available on this SCC-AS node, then the SCCCDMAReOrigination feature queries cassandra, using the request URI’s digits as the correlation ID.

Note

The cassandra query result may return:

  1. valid call information

  2. expired call information, if the allocation of the correlation ID has expired

  3. no call information, if there is no call information for the correlation ID

If correlation data is not found, the feature finishes execution without modifying any state.

If a P-Asserted-Identity header is present on the incoming INVITE, and a phone number can be extracted from it, it is normalised and compared to the (normalised) calling party number extracted from the ORREQ or ANLYZD. If they are different, the request is rejected with a 403 response. This functionally can be disabled using the PoliceOriginatingRequests configuration flag.

Next, the feature then retrieves the S-CSCF name for the calling party from either of two places based on the SkipHSSLookup flag:

Flag Value Effect

TRUE

Use the value in DirectRoutingURI from network configuration.

FALSE

Do a lookup from the HSS through the Sh Cache Microservice RA and the Sh Cache Microservice.

The feature then adjusts or sets various headers in the outgoing INVITE.

Finally, the Sentinel SIP instance hosting this feature acts as a B2BUA between the I-CSCF and the S-CSCF.

Releasing a Correlation ID

If the OriginationRequest or AnalyzedInformation and the reoriginated SIP INVITE are received on the same SCC-AS node, then the allocated correlation ID is released when the call information data is returned by the correlation RA.

If the reoriginated SIP INVITE is received on a different SCC-AS node then the correlation ID is released by sending a SIP MESSAGE to the SCC-AS node that received the OriginationRequest or AnalyzedInformation, which releases the correlation ID via the correlation RA on that node.

SIP headers in the outgoing INVITE

The feature sets or adjusts the following headers in the outgoing INVITE:

Header Name Change

Request-URI

Set to a tel URI with the digits being the original IDP’s called party number digit string (non-BCD encoded).

To

Set to the original IDP’s called party number digit string (non-BCD encoded).

History-Info

If only one such header exists on the INVITE, it is removed.

P-Asserted-Identity

If it is not present in the INVITE it is set to a tel URI using the calling party number from the original IDP.

Privacy

Set to ONLY_IDENTITY if the original IDP has presentation RESTRICTED or NETWORK_RESTRICTED.

Route

A new route to the S-CSCF for the served user is added, if the feature was invoked on an originating trigger an orig parameter will be included.

OC-Billing-ID

The BillingID from the OriginationRequest or AnalyzedInformation.

P-Profile-Key

If such header exists in the INVITE, it is removed.

Note The OC-Billing-ID is a proprietary header created by OpenCloud. The OC-Billing-ID header is added so the original CDMA request can be correlated with the ongoing SIP session when it reaches MMTel.
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Sentinel VoLTE Version 4.1