9.3 Mn Signalling procedures

29.1633GPPInterworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networksTS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

This clause describes of logical signalling procedures (i.e. message identifiers are not part of the protocol) between the MGCF and IM-MGW. The procedures within this clause are intended to be implemented using the standard H.248 procedure as defined in] ITU recommendation H.248.1 [2] with appropriate parameter combinations.

9.3.1 Procedures related to terminations towards the IM CN Subsystem

A mapping of the procedures defined here to H.248 procedures and parameters is provided in 3GPP TS 29.332 [15].

9.3.1.1 Reserve IMS connection point

This procedure is used to reserve local connection addresses and local resources.

Table 25: Procedures toward the IM Subsystem: Reserve IMS connection point

Procedure	Initiated	Information element name	Information element required	Information element description
Reserve IMS Connection Point	MGCF	Context/Context Request	M	This information element indicates the existing context or requests a new context for the bearer termination.
		Priority information	O	This information element requests the IM-MGW to apply priority treatment for the terminations and bearer connections in the specified context.
		IMS Termination Request	M	This information element requests a new IMS termination for the bearer to be established.
		Local IMS Resources/	M	This information element indicates the resource(s) (i.e. codecs) for which the IM-MGW shall be prepared to receive user data,
		IP Interface Type	O	This information element indicates the used interface type
		ReserveValue	O	This information element indicates if multiple local IMS resources are to be reserved.
		Local Connection Addresses Request	M	This information element requests an IP address and port number on the IM-MGW that the remote end can send user plane data to.
		Notify termination heartbeat	M	This information element requests termination heartbeat indications.
		Notify Released Bearer	O	This information element requests a notification of a released bearer.
		IP Realm Identifier	O	This information element indicates the IP realm of the IP termination.
		ECN Enable	O	This information element requests the IM-MGW to apply ECN procedures
		ECN Initiation Method	C	This information element specifies the ECN Initiation method and requests the IM-MGW to perform IP header settings as an ECN endpoint. It may be included only if ECN is enabled.
		Notify ECN Failure Event	C	This information element requests a notification if an ECN failure occurs. It may only be supplied if ECN is enabled.
		Diffserv Code Point	O	This information element requests the IM-MGW to apply a specific Diffserv Code Point to the IP headers.
		ICE password request	O	This information element is present if MGCF requests an ICE password.
		ICE Ufrag request	O	This information element is present if MGCF requests an ICE ufrag.
		ICE host candidate request	O	This information element is present if MGCF requests an ICE host candidate.
		ICE pacing request	O	This information element is present if MGCF requests a pacing value for connectivity checks (Ta timer value). It is only applicable for full ICE.
		STUN server request	O	This information element is present if MGCF requests the IM-MGW to answer STUN connectivity checks for ICE.
		SDPCapNeg configuration	O	This information element provides SDPCapNeg configuration(s) using as "a=acap", "a=tcap", "a=pcfg" and "a=acfg" SDP attributes.
Reserve IMS Connection Point Ack	IM-MGW	Context	M	This information element indicates the context where the command was executed.
		IMS Termination	M	This information element indicates the IMS termination where the command was executed.
		Local IMS Resources	M	This information element indicates the resources that the IM-MGW has reserved to receive the user plane data from the IMS.
		Local Connection Addresses	M	This information element indicates the IP address and port on the IM-MGW that shall receive user plane data from IMS.
		ICE password	C	This information element shall be present only if it was contained in the request. It indicates the ICE password assigned by the IM-MGW.
		ICE Ufrag	C	This information element shall be present only if it was contained in the request. It indicates the ICE Ufrag assigned by the IM-MGW.
		ICE host candidate	C	This information element shall be present only if it was contained in the request. It indicates the ICE host candidate assigned by the IM-MGW.
		ICE pacing	C	This information element shall be present only if it was contained in the request. It indicates a desired pacing value for connectivity checks (Ta timer value).
		ICE lite indication	C	This information element shall be present only if an ICE host candidate request was contained in the request, and the IM-MGW supports ICE lite, but not full ICE. It indicates that the IM-MGW only supports ICE lite.
		SDPCapNeg configuration	C	This information element shall be present only if it was contained in the request. It provides SDPCapNeg configuration(s) using as "a=acap", "a=tcap", "a=pcfg" and "a=acfg" SDP attributes.

9.3.1.2 Configure IMS resources

This procedure is used to select multimedia-processing resources for an Mb interface connection.

Table 26: Procedures toward the IM Subsystem: Select Local,
Select Remote IMS Processing Resource

Procedure	Initiated	Information element name	Information element required	Information element description
Configure IMS Resources	MGCF	Context	M	This information element indicates the existing context.
		IMS Termination	M	This information element indicates the existing bearer termination.
		Local IMS Resources	O	This information element indicates the resources (i.e. codec) that the IM-MGW may use on the reception of user plane data.
		Remote IMS Resources	M	This information element indicates the resources (i.e. codec) that the IM-MGW may send user plane data to.
		Local Connection Addresses	O	This information element indicates the IP address and port on the IM-MGW that the IMS user can send user plane data to.
		Remote Connection Addresses	M	This information element indicates the IP address and port that the IM-MGW can send user plane data to.
		IP Interface Type	O	This information element indicates the used interface type
		Reserve Value	O	This information element indicates if multiple IMS resources are to be reserved.
		Remote Connection Addresses Source Filter	O	This information element indicates an optional source filter restricting the IP addresses and ports that the IM-MGW shall accept as source for incoming user plane data. If this information element is set, the IM-MGW shall silently discard incoming user plane data from disallowed sources.
		ECN Enable	O	This information element requests the IM-MGW to apply ECN procedures.
		ECN Initiation Method	C	This information element specifies the ECN Initiation method and requests the IM-MGW to perform IP header settings as an ECN endpoint. It may be included only if ECN is enabled.
		Notify ECN Failure Event	C	This information element requests a notification if an ECN failure occurs. It may only be supplied if ECN is enabled.
		ICE Connectivity Check	C	This information element requests the IM-MGW to perform ICE connectivity check as defined by IETF RFC 8445 [156]. It is only applicable for full ICE.
		Notify ICE Connectivity Check Result	C	This information element requests a notification of ICE connectivity check result. It is only applicable for full ICE.
		Notify New Peer Reflexive Candidate	C	This information element requests a notification of new peer reflexive candidate was discovered during a connectivity check. It is only applicable for full ICE.
		Additional ICE Connectivity Check	C	This information element requests the IM-MGW to perform additional ICE connectivity check as defined by IETF RFC 8445 [156]. It is only applicable for full ICE.
		ICE received candidate	O	This information element is present if MGCF indicates a received candidate for ICE.
		ICE received password	O	This information element is present if MGCF indicates a received password for ICE.
		ICE received pacing	O	This information element is present if MGCF indicates a received pacing value for connectivity checks (Ta timer value). It is only applicable for full ICE.
		Allowed RTCP APP message types	O	This information element is present if the MGCF allows the IM-MGW to send RTCP APP packets of the indicated types. The IM-MGW shall not send other RTCP APP packets. If the parameter is not supplied, the IM-MGW shall not send any RTCP APP packets.
		SDPCapNeg configuration	O	This information element provides SDPCapNeg configuration(s) using as "a=acap", "a=tcap", "a=pcfg" and "a=acfg" SDP attributes.
		Additional Bandwidth Properties	O	This information element indicates additional bandwidth properties using "a=bw-info" SDP attribute(s) as defined by 3GPP TS 26.114 [104].
Configure IMS Resources Ack	IM-MGW	Context	M	This information element indicates the context where the command was executed.
		IMS Termination	M	This information element indicates the IMS termination where the command was executed.
		Local IMS Resource	O	This information element indicates the resources that the IM-MGW has reserved to receive the user plane data from the far end.
		Remote IMS Resource	M	This information element indicates the resource (i.e. codec) that the IM-MGW shall use to send user data to.
		Local Connection Address	O	This information element indicates the IP address and port on the IM-MGW that the remote end can send user plane data to.
		Remote Connection Address	M	This information element indicates the IP address and port that the IM-MGW can send user plane data to.

9.3.1.3 Reserve IMS Connection point and configure remote resources

This procedure is used to reserve multimedia-processing resources for an Mb interface connection.

Table 27: Procedures toward the IM Subsystem: reserve local, reserve remote IMS connection point

Procedure	Initiated	Information element name	Information element required	Information element description
Reserve IMS Connection Point and Configure Remote Resources	MGCF	Context/Context Request	M	This information element indicates the existing context or requests a new context for the bearer termination.
		Priority information	O	This information element requests the IM-MGW to apply priority treatment for the terminations and bearer connections in the specified context.
		IMS Termination/IMS Termination Request	M	This information element indicates the existing bearer termination or requests a new IMS termination for the bearer to be established.
		Local IMS Resources	M	This information element indicates the resource(s) (i.e. codecs) for which the IM-MGW shall be prepared to receive user data,
		Remote IMS Resources	M	This information element indicates the resources (i.e. codec) that the IM-MGW shall use to send user data in the IMS.
		IP Interface Type	O	This information element indicates the used interface type
		Reserve Value	O	This information element indicates if multiple IMS resources are to be reserved.
		Local Connection Address request	M	This information element requests an IP address and a port number on the IM-MGW that the remote end can send user plane data to.
		Remote Connection Addresses	M	This information element indicates the IP address and ports at an IMS user that the IM-MGW can send user plane data to.
		Notify termination heartbeat	M	This information element requests termination heartbeat indications.
		Notify Released Bearer	O	This information element requests a notification of a released bearer.
		IP Realm Identifier	O	This information element indicates the IP realm of the IP termination.
		ECN Enable	O	This information element requests the IM-MGW to apply ECN procedures and IP header settings as an ECN endpoint.
		ECN Initiation Method	C	This information element specifies the ECN Initiation method and requests the IM-MGW to perform IP header settings as an ECN endpoint. It may be included only if ECN is enabled.
		Notify ECN Failure Event	C	This information element requests a notification if an ECN failure occurs. It may only be supplied if ECN is enabled.
		Diffserv Code Point	O	This information element requests the IM-MGW to apply a specific Diffserv Code Point to the IP headers.
		STUN server request	O	This information element is present if MGCF requests the IM-MGW to answer STUN connectivity checks for ICE.
		ICE Connectivity Check	C	This information element requests the IM-MGW to perform ICE connectivity check as defined by IETF RFC 8445 [156]. It is only applicable for full ICE.
		Notify ICE Connectivity Check Result	C	This information element requests a notification of ICE connectivity check result. It is only applicable for full ICE.
		Notify New Peer Reflexive Candidate	C	This information element requests a notification of new peer reflexive candidate was discovered during a connectivity check. It is only applicable for full ICE.
		ICE password request	O	This information element is present if MGCF requests an ICE password.
		ICE Ufrag request	O	This information element is present if MGCF requests an ICE ufrag.
		ICE host candidate request	O	This information element is present if MGCF requests an ICE host candidate.
		ICE pacing request	O	This information element is present if MGCF requests a pacing value for connectivity checks (Ta timer value). It is only applicable for full ICE.
		ICE received candidate	O	This information element is present if MGCF indicates a received candidate for ICE.
		ICE received password	O	This information element is present if MGCF indicates a received password for ICE.
		ICE received Ufrag	O	This information element is present if MGCF indicates a received Ufrag for ICE.
		ICE received pacing	O	This information element is present if MGCF indicates a received pacing value for connectivity checks (Ta timer value). It is only applicable for full ICE.
		Allowed RTCP APP message types	O	This information element is present if the MGCF allows the IM-MGW to send RTCP APP packets of the indicated types. The IM-MGW shall not send other RTCP APP packets. If the parameter is not supplied, the IM-MGW shall not send any RTCP APP packets.
		SDPCapNeg configuration	O	This information element provides SDPCapNeg configuration(s) using as "a=acap", "a=tcap", "a=pcfg" and "a=acfg" SDP attributes.
		Additional Bandwidth Properties	O	This information element indicates additional bandwidth properties using "a=bw-info" SDP attribute(s) as defined by 3GPP TS 26.114 [104].
Reserve IMS Connection Point and Configure Remote Resources Ack	IM-MGW	Context	M	This information element indicates the context where the command was executed.
		IMS Termination	M	This information element indicates the IMS termination where the command was executed.
		Local IMS Resources	M	This information element indicates the resources that the IM-MGW has reserved to receive the user plane data from IMS.
		Remote IMS Resources	M	This information element indicates the resource (i.e. codec) that the IM-MGW shall use to send user data.
		Local Connection Addresses	M	This information element indicates the IP address on the IM-MGW that shall receive user plane data from the IMS.
		ICE password	C	This information element shall be present only if it was contained in the request. It indicates the ICE password assigned by the IM-MGW.
		ICE Ufrag	C	This information element shall be present only if it was contained in the request. It indicates the ICE Ufrag assigned by the IM-MGW.
		ICE host candidate	C	This information element shall be present only if it was contained in the request. It indicates the ICE host candidate assigned by the IM-MGW.
		ICE lite indication	C	This information element shall be present only if an ICE host candidate request was contained in the request, and the IM-MGW supports ICE lite, but not full ICE. It indicates that the IM-MGW only supports ICE lite.
		ICE pacing	C	This information element shall be present only if it was contained in the request. It indicates a desired pacing value for connectivity checks (Ta timer value).
		SDPCapNeg configuration	C	This information element shall be present only if it was contained in the request. It provides SDPCapNeg configuration(s) using as "a=acap", "a=tcap", "a=pcfg" and "a=acfg" SDP attributes.

9.3.1.4 Release IMS termination

This procedure is used by the MGCF to release a termination towards the IMS and free all related resources.

Table 28: Release IMS termination

Procedure	Initiated	Information element name	Information element required	Information element description
Release IMS Termination	MGCF	Context	M	This information element indicates the context for the bearer termination.
Release IMS Termination	MGCF	Bearer Termination	M	This information element indicates the bearer termination to be released.
Release IMS Termination Ack	IM-MGW	Context	M	This information element indicates the context where the command was executed.
Release IMS Termination Ack	IM-MGW	Bearer Termination	M	This information element indicates the bearer termination where the command was executed.

9.3.1.5 Detect IMS RTP Tel event

This procedure is used by the MGCF to request from the MGW the detection of telephony events signalled within RTP according to RFC 4733 [105] and the notification of received telephony events. This procedure is the same as that is defined in the clause "Detect DTMF" in 3GPP TS 23.205 [27].

Table 29: VOID

9.3.1.6 Notify IMS RTP Tel event

This procedure is used by the MGW to notify the MGCF about the detection of telephony events signalled within RTP according to RFC 4733 [105]. This procedure is the same as that defined in the clause "Report DTMF" in 3GPP TS 23.205 [27].

Table 30: VOID

9.3.1.7 Void

9.3.1.8 Send IMS RTP Tel event

This procedure is used by the MGCF to request from the MGW to signal a telephone event within RTP according to RFC 4733 [105]. This procedure is the same as that defined in the clause "Send DTMF" in 3GPP TS 23.205 [27].

9.3.1.9 Stop IMS RTP Tel event

This procedure is used by the MGW to request from the MGW to stop signalling a telephone event within RTP according to RFC 4733 [105]. This procedure is the same as that defined in the clause "Stop DTMF" in 3GPP TS 23.205 [27].

9.3.1.10 Termination heartbeat indication

This procedure is used to report indication of hanging termination.

Table 30a: Procedures between (G)MSC server and MGW: Hanging termination indication

Procedure	Initiated	Information element name	Information element required	Information element description
Termination heartbeat indication	MGW	Context	M	This information element indicates the context for the bearer termination.
		Bearer Termination	M	This information element indicates the bearer termination for which the termination heartbeat is reported.
		Termination heartbeat	M	Hanging Termination event, as defined in TS 29.332 [15].
Termination heartbeat indication Ack	(G)MSC-S	Context	M	This information element indicates the context where the command was executed.

9.3.1.11 IMS Bearer Released

This procedure is used by the IM-MGW to indicate towards the MGCF that an error occurred on an IMS termination which requires the release of the termination. This procedure is the same as that defined in the clause "Bearer Released" in 3GPP TS 23.205 [27].

9.3.1.12 End IMS RTP Tel event

This procedure is used by the MGCF to indicate to the IM-MGW to stop detection of telephony events signalled within RTP according to IETF RFC 4733 [105]. This procedure is the same as that is defined in the clause "Stop Detect DTMF" in 3GPP TS 23.205 [27].

9.3.1.13 IMS Send Tone

This procedure is used by the MGCF to order the IM-MGW to generate a tone at termination towards IMS. This procedure is the same as that defined in the clause "Send Tone" in 3GPP TS 23.205 [27].

9.3.1.14 IMS Stop Tone

This procedure is used by the MGCF to order the IM-MGW to stop generating a tone at a termination towards IMS. This procedure is the same as that defined in the clause "Stop Tone" in 3GPP TS 23.205 [27].

9.3.1.15 IMS Tone Completed

This procedure is used by the IM-MGW to indicate to the MGCF that a tone has finished being generated at a termination. This procedure is the same as that defined in the clause "Tone Completed" in 3GPP TS 23.205 [27].

9.3.1.16 ECN Failure Indication

This procedure is used to report ECN related errors (see clause 9.2.11.1c).

Table 9.3.1.16.1: Procedures toward the IM Subsystem: ECN Failure Indication

Procedure	Initiated	Information element name	Information element required	Information element description
ECN Failure Indication	IM-MGW	Context	M	This information element indicates the context for the bearer termination.
		Bearer Termination	M	This information element indicates the bearer termination for which the ECN failure is reported.
		ECN Failure Indication	M	This IE indicates an ECN failure event.
ECN Failure Indication Ack	MGCF	Context	M	This information element indicates the context where the command was executed.
ECN Failure Indication Ack	MGCF	Bearer Termination	M	This information element indicates the bearer termination where the command was executed

9.3.1.17 ICE Connectivity Check Result Notification

This procedure is used to report ICE connectivity check result for Full ICE.

Table 9.3.1.17.1: Procedures between MGCF and IM-MGW: ICE Connectivity Check Result Notification

Procedure	Initiated	Information element name	Information element required	Information element description
ICE Connectivity Check Result Notification	IM-MGW	Context	M	This information element indicates the context for the bearer termination.
		Bearer Termination	M	This information element indicates the bearer termination for which the ICE Connectivity Check Result is reported.
		ICE Connectivity Check Result	M	This information element indicates an ICE Connectivity Check Result event.
ICE Connectivity Check Result Notification Ack	MGCF	Context	M	This information element indicates the context where the command was executed.
ICE Connectivity Check Result Notification Ack	MGCF	Bearer Termination	M	This information element indicates the bearer termination where the command was executed.

9.3.1.18 ICE New Peer Reflexive Candidate Notification

This procedure is used to report ICE new peer reflexive candidate for Full ICE.

Table 9.3.1.18.1: Procedures between MGCF and IM-MGW: ICE New Peer Reflexive Candidate Notification

Procedure	Initiated	Information element name	Information element required	Information element description
ICE New Peer Reflexive Candidate Notification	IM-MGW	Context	M	This information element indicates the context for the bearer termination.
		Bearer Termination	M	This information element indicates the bearer termination for which the ICE New Peer Reflexive Candidate is reported.
		ICE New Peer Reflexive Candidate	M	This information element indicates an ICE New Peer Reflexive Candidate event.
ICE New Peer Reflexive Candidate Notification Ack	MGCF	Context	M	This information element indicates the context where the command was executed.
ICE New Peer Reflexive Candidate Notification Ack	MGCF	Bearer Termination	M	This information element indicates the bearer termination where the command was executed.

9.3.2 Procedures related to a termination towards an ISUP network

A mapping of the procedures defined here to H.248 procedures and parameters is provided in 3GPP TS 29.332 [15].

9.3.2.1 Reserve TDM circuit

This procedure is used by the MGCF to reserve a TDM circuit in the IM-MGW towards the preceding/succeeding CS network element.

Table 31: Reserve TDM circuit procedure

Procedure	Initiated	Information element name	Information element required	Information element description
Reserve TDM Circuit	MGCF	Context/Context Request	M	This information element indicates the existing context or requests a new context for the bearer termination.
		Bearer Termination	M	This information element indicates the physical bearer termination for the TDM circuit.
		Bearer Service Characteristics	M	This information element indicates the bearer service requested by the user.
		Notify termination heartbeat	O	This information element requests termination heartbeat indications.
		Notify Released Bearer	O	This information element requests a notification of a released bearer
Reserve Circuit Ack	IM-MGW	Context	M	This information element indicates the context where the command was executed.

9.3.2.2 Change TDM through-connection

This procedure is used by the MGCF to modify the through-connection (forward, backward, both-way, inactive) of a TDM termination at the IM-MGW towards the PSTN.

This procedure is the same as Change Through Connection in 3GPP TS 23.205 [27].

9.3.2.3 Activate TDM voice-processing function

This procedure is used by the MGCF to activate or de-activate a voice processing function of a TDM termination at the IM-MGW towards the PSTN. This voice processing function may include a cancellation for electronic echoes.

This procedure is the same as Activate Voice Processing Function in 3GPP TS 23.205 [27].

9.3.2.4 Send TDM tone

This procedure is used by the MGCF to order the IM-MGW to generate a tone at a TDM termination towards the PSTN.

This procedure is the same as Send Tone in 3GPP TS 23.205 [27].

9.3.2.5 Stop TDM tone

This procedure is used by the MGCF to order the IM-MGW to stop generating a tone at a TDM termination towards the PSTN.

This procedure is the same as Stop tone in 3GPP TS 23.205 [27].

9.3.2.6 Play TDM announcement

This procedure is used by the MGCF to order the IM-MGW to generate an announcement at a TDM termination towards the PSTN. The MGCF may request a notification that the announcement is completed. This procedure is the same as Play Announcement in 3GPP TS 23.205 [27]. This procedure is optional.

9.3.2.7 TDM announcement completed

This procedure is used by the IM-MGW to notify the MGCF that an announcement at a TDM termination towards the PSTN is completed. This procedure is the same as Announcement Completed in 3GPP TS 23.205 [27]. This procedure is optional.

9.3.2.8 Stop TDM announcement

This procedure is the same as Stop Announcement 3GPP TS 23.205 [27]. This procedure is used by the MGCF to order the IM-MGW to stop generating an announcement at a TDM termination towards the PSTN. This procedure is optional.

9.3.2.9 Continuity check

This procedure is used by the MGCF to order the IM-MGW to generate a continuity check tone at a TDM termination towards the PSTN and to inform the MGCF about the result of the continuity check as soon as the continuity check tone is received or a time-out occurs. This procedure is optional.

Table 32: Continuity check procedure

Procedure	Initiated	Information element name	Information element required	Information element description
Continuity check	MGCF	Context/Context Request	M	This information element indicates the existing context or requests a new context for the bearer termination.
		TDM Termination	M	This information element indicates the existing bearer termination
		Request for continuity tone sending	M	This information request the IM-MGW to apply the continuity check procedure on the indicated TDM termination
		Request for continuity check tone detection	M	This information request the IM-MGW to inform e continuity check procedure on the indicated TDM termination

9.3.2.10 Continuity check verify

This procedure is used by the IM-MGW to indicate towards the MGCF that the continuity check at a TDM termination towards the PSTN has been completed and to return the result of the check: success or failure. This procedure is optional.

Table 33: Continuity check verify procedure

Procedure	Initiated	Information element name	Information element required	Information element description
Continuity check Verify	IM-MGW	Context/t	M	This information element indicates the context where the command was executed.
		TDM Termination	M	This information element indicates the TDM termination involved in the procedure
		Outcome of the continuity check	M	This information element indicates the outcome of the continuity check (successful/unsuccessful)

9.3.2.11 Continuity check response

This procedure is used by the MGCF to order the IM-MGW to loop back an incoming continuity check tone at a TDM termination towards the PSTN. This procedure is optional.

Table 34: Continuity check response procedure

Procedure	Initiated	Information element name	Information element required	Information element description
Continuity check response	MGCF	Context/Context Request	M	This information element indicates the existing context or requests a new context for the bearer termination.
		TDM Termination	M	This information element indicates the existing bearer termination
		Request for loop back of the continuity tone	M	This information request the IM-MGW to loop back the continuity check tone on the indicated TDM termination

9.3.2.12 Release TDM termination

This procedure is used by the MGCF to release a TDM termination at the IM-MGW towards the PSTN and free all related resources.

Table 35: Release TDM termination procedure

Procedure	Initiated	Information element name	Information element required	Information element description
Release TDM Termination	MGCF	Context	M	This information element indicates the context for the bearer termination.
Release TDM Termination	MGCF	Bearer Termination	M	This information element indicates the bearer termination to be released.
Release TDM Termination Ack	IM-MGW	Context	M	This information element indicates the context where the command was executed.
Release TDM Termination Ack	IM-MGW	Bearer Termination	M	This information element indicates the bearer termination where the command was executed.

9.3.2.13 Termination Out-of-Service

This procedure is used by the IM-MGW to indicate towards the MGCF that one or several physical termination(s) will go out of service. This procedure is the same as Termination Out-of-Service in 3GPP TS 23.205 [27].

9.3.2.14 Termination heartbeat indication

This procedure is used to report indication of hanging termination.

Table 35a: Procedures between (G)MSC server and MGW: Hanging termination indication

Procedure	Initiated	Information element name	Information element required	Information element description
Termination heartbeat indication	MGW	Context	M	This information element indicates the context for the bearer termination.
		Bearer Termination	M	This information element indicates the bearer termination for which the termination heartbeat is reported.
		Termination heartbeat	M	Hanging termination event, as defined in TS 29.332 [15].
Termination heartbeat indication Ack	(G)MSC-S	Context	M	This information element indicates the context where the command was executed.

9.3.2.15 Bearer Released

This procedure is used by the IM-MGW to indicate towards the MGCF that an error occurred on a physical termination which requires the release of the termination. This procedure is the same as Bearer Released in 3GPP TS 23.205 [27].

9.3.2.16 TDM tone completed

This procedure is used by the IM-MGW to MGCF to indicate that a tone has finished being generated at a TDM termination.

This procedure is the same as Tone Completed in 3GPP TS 23.205 [27].

9.3.3 Procedures related to a termination towards a BICC network

The call related procedures detailed in table 36 shall be supported. Those procedures are defined in 3GPP TS 29.332 [15].

Table 36: Required procedures defined in TS 29.332 [15]

Procedure defined in TS 29.332 [15]	Remarks
Establish Bearer
Prepare Bearer
Change Through-Connection
Release Bearer
Release Termination
Bearer Established
Bearer Released
Send Tone
Stop Tone
Tone completed
Play Announcement	Optional
Stop Announcement	Optional
Announcement Completed	Optional
Confirm Char	Optional
Modify Bearer Characteristics	Optional
Reserve Char	Optional
Bearer Modified	Optional
Activate Voice Processing Function	Optional
Tunnel Information Down	Conditional: For IP Transport at BICC termination
Tunnel Information Up	Conditional: For IP Transport at BICC termination
Termination Out-of-Service
Termination heartbeat indication

9.3.4 Non-call related procedures

The procedures from 3GPP TS 23.205 [27] detailed in table 37 shall be applied for the IM‑MGW handling component of the Mn interface.

Table 37: Non-call related procedures

Procedure defined in TS 29.332 [15]	Corresponding Procedure defined in TS 23.205 [27]	Remarks
IM-MGW Out of service	MGW Out of Service
IM-MGW Communication Up	MGW Communication Up
IM-MGW Restoration	MGW Restoration
IM-MGW Register	MGW Register
IM-MGW Re-register	MGW Re-register
MGCF Ordered Re-register	(G)MSC Server Ordered Re-register
MGCF Restoration	(G)MSC Server Restoration
MGCF Out of Service	(G)MSC Server Out of Service
Termination Out-of-Service	Termination Out-of-Service	The "Termination Out-of-Service procedure" is used as call-related H.248 command as well
Termination Restoration	Termination Restoration
Audit Value	Audit Value
Audit Capability	Audit Capability
Command Rejected	Command Rejected	The "Command Rejected" procedure may be used in response both to call-related and non-call-related H.248 Commands.
IM-MGW Capability Change	Capability Update
IM-MGW Resource Congestion Handling – Activate	MGW Resource Congestion Handling – Activate
IM-MGW Resource Congestion Handling – Indication	MGW Resource Congestion Handling – Indication
Control association monitoring	Control association monitoring
Inactivity timeout activation	Inactivity timeout activation
Inactivity timeout indication	Inactivity timeout indication
Hanging termination detection	Hanging termination detection
Hanging termination detection	Hanging termination detection

9.3.5 Multiple IP Realms

The procedures to support multiple IP realms in the present clause are optional.

Figure 9.3.5.1 shows a scenario where multiple IP realms are applied.

Figure 9.3.5.1 Multiple IP realms scenario

Shown in figure 9.3.5, the IM CN1 and CS CN1 represent separate IP realms. The definition of IP realm is specified in IETF RFC 2663[90].

The termination1 and termination2 are connected with different IP realms in the IM-MGW separately.

For establishing session when multiple IP realms are used in the IM-MGW, the MGCF may indicate the IP realm identifier to the IM-MGW. The IM-MGW shall assign the IP termination with the indicated IP realm.

A default IP realm may be configured in IM-MGW such that if the IM-MGW has not received the IP realm identifier and the IM-MGW supports multiple IP realms then the default IP realm shall be used.

If the IM-MGW does not support the option to indicate an IP realm then it is free to select any IP port.