The Conference factory PSI is a SIP URI or TEL URL that is a conferencing service Public Service Identity.

There are two reasons to support multiple conference factory PSI:

  • support conference factory PSIs defined by relevant standards (Standard conference factory PSI)

  • support operators that are live with handsets that use non-compliant conference factory PSI (Alias conference factory PSI)

Standard Conference Factory PSI

A standard conference factory PSI is one that conforms to 3GPP TS 23.003.

Understanding Standard Conference Factory PSIs

3GPP TS 23.003 lists three conference factory PSI formats that could be required in a network:

  • sip:mmtel@conf-factory.<domain>

  • sip:mmtel@conf-factory.ims.mnc<MNC>.mcc<MCC>

  • sip:conf-factory.ics.mnc<MNC>.mcc<MCC>

where <domain>, <MCC> and <MNC> correspond to properties of the platform.

The relevant sections of 3GPP TS 23.003 include:

The Conference Factory URI shall take the form of a SIP URI (see IETF RFC 3261 [26]) with a host portion set to the home network domain name as described in subclause 20.3.2 prefixed with "conf-factory.". An example using the same example IMSI from sub-clause 20.3.2 can be found below:

EXAMPLE: "". The user portion of the SIP URI is optional and implementation specific.

— 3GPP TS 23.003
section 20.3.5 Conference Factory URI

The home network domain name shall be in the form of an Internet domain name, e.g., as specified in IETF RFC 1035 [19].

— 3GPP TS 23.003
section 20.3.2 Home network domain name

The values that parameterise standard conference PSIs (such as MCC/MNC) are in the configuration for the PLMN ID Analyser Component and the configuration profile defined in Sentinel SIP.

Checking standard MMTel conference factory PSI

The set of standard conference factory PSIs supported is derived from the Sentinel SIP Configuration profile and the PLMN ID Analyser Component. For example, if HomeNetworkIds is set to and the configured home PLMN IDs are (254,01) and (254,17), the set of standard conference factory PSIs is:






If no matching standard conference factory PSI is found, then check all alias conference factory PSI.

Alias Conference Factory PSI

An Alias conference factory PSI is a non-standard conference PSI used by a handset that does not conform to standards.

Supporting Alias conference factory PSI

The MMTelConf configuration profile (from the MMTelCONFConfigProfileTable table) defines a property AliasConferenceFactoryPSI. This property is a set of Strings that identify non-standard conference factory PSI that should be recognised by the platform. Each String must be a valid SIP URI or Tel URL.

Checking Alias conference factory PSI

Each entry in the alias conference factory PSI set is a String that is a constant or parameterised by:

  • <HOME-DOMAIN> — replace with home domains configured for the platform

  • <MCC> and <MNC> — replace with home PLMN IDs configured for the platform

For example, if HomeNetworkIds is set to and the configured home PLMN IDs are (254,01) and (254,17),

and …​

Property Value


then the supported alias conference factory PSIs are:








If no matches are found, then this trigger is not relevant for MMTel Conferencing. The feature will end, and control will return to the Sentinel runtime.

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Sentinel VoLTE Version 4.0.0