C.8 Registration of MME for SMS

23.2723GPPCircuit Switched (CS) fallback in Evolved Packet System (EPS)Release 17Stage 2TS

C.8.1 Request for registration

An MME supporting SMS in MME that needs to perform a registration with HSS shall follow the following procedure to become registered by the HSS also for SMS.

The following sequence shows the request for registration with the HSS for SMS in MME.

Figure C.8.1-1: MME registration for SMS

1. The UE initiates combined attach or combined TA/LA Update to an MME. A UE that only supports NB-IoT (see TS 23.401 [2]) may issue an EPS attach or TA Update instead of a combined attach or combined TA/LA Update.

2. The MME sends a Location Update Request (SMS in MME feature flag, MME address for MT-SMS routing, RegistrationForSMSRequest, "SMS-only" Indication) message to HSS. SMS in MME feature flag indicates that the MME is capable of SMS transfer without the need of establishing an SGs association with an MSC. The "SMS-only" Indication is included if it has been included in the request from the UE. The MME includes one of the following RegistrationForSMSRequest values based on the criteria shown in Table C.8.1-1.

Table C.8.1-1: Registration For SMS Request values

Value

Description

SMS in MME Required

– MME does not support SGs; or

– The MME can be configured to use this value when the UE indicates "SMS only" or when known that the subscription is "PS and SMS only".

NOTE 1

SMS in MME Not Preferred

– The MME can be configured to use this value when the UE indicates "SMS only" or when known that the subscription is "PS and SMS only"

– The MME can be configured to use this value when the UE does not indicate "SMS only" (i.e. requests CSFB) and the MME has no subscriber data yet (when MME is configured to use SGs for "SMS and PS only" subscription).

NOTE 2

No Preference for SMS in MME

– The MME has no preference configured to use SMS in MME or SGs, but both options are available from MME perspective.

NOTE 2

NOTE 1: If this is set the HSS cannot determine whether the SGs is available.

NOTE 2: If this value is set it means that the MME supports SGs. UE might or might not indicate "SMS-only".

3. If the HSS supports SMS in MME and the subscription includes SMS:

a) if one or more of the following is true:

– Network Access Mode is PS only; or

– the MME indicates "SMS in MME Required";

then the HSS shall register the MME for SMS;

b) if the MME indicates "No Preference for SMS in MME" and Network Access Mode is not equal to PS only but one or more of the following are true:

– the UE indicated "SMS-only";

– the subscription is limited to PS domain services and SMS service via the CS and the PS domain ("PS and SMS only");

then the HSS should register the MME for SMS;

NOTE 3: The HSS can decide not to register the MME for SMS since it knows that the MME supports SGs but the normal behaviour would be to register for SMS and avoid an SGs association.

c) if the MME indicates "SMS in MME Not Preferred" and Network Access Mode is not equal to PS only then the HSS should not register the MME for SMS;

NOTE 4: The HSS can decide to register the MME for SMS based on the "PS and SMS only" setting and also on other factors including the UE indication for "SMS-Only", it is however assumed the normal behaviour would be not to register for SMS.

d) otherwise the HSS shall not register the MME for SMS.

If HSS registered the MME for SMS, the HSS stores the MME address for MT SMS.

4. If the HSS accepts to register the MME identity as an MSC identity for terminating SMS services then the HSS cancels the MSC/VLR registration from the HSS.

5. The HSS sends a Location Update Answer (indication whether the MME has been registered for SMS, subscription data including the Network Access Mode and "PS and SMS only" indications, SMS subscription data, SMS in MME feature flag) message to MME.

If the HSS does not register the MME for SMS, it shall indicate that the MME has not been registered for SMS and not include any SMS subscription data.

SMS in MME feature flag indicates that the HSS is capable of supporting the SMS in MME feature.

The MME stores the returned data and checks the result of registering the MME for SMS.

If the registration for SMS was not accepted, the MME does following:

a. For a PS-only subscription (i.e. the Network Access Mode in the subscription equals "PS-only"), the MME shall not establish any SGs association (no SMS services are provided to the UE).

b. For a "PS and SMS only" subscription where SMS can be provided over CS (i.e. the Network Access Mode equals "PS+CS" and the subscription parameter "PS and SMS only" is set), the MME tries to establish SGs for SMS.

c. For a PS and CS subscription where also other CS services are allowed (i.e. Network Access Mode equals "PS+CS" and the subscription parameter "PS and SMS only" is not set), the MME tries to establish SGs for SMS and other CS services.

C.8.2 Removal of registration of MME for SMS

C.8.2.0 General

The removal of the registration of MME for SMS is used by:

– The HSS to inform the MME that the registration of MME for SMS is cancelled; or by

– The MME to inform the HSS that it requests to remove its registration for SMS.

C.8.2.1 HSS-initiated removal of registration of MME for SMS

When the HSS needs to indicate to the MME that it is no longer registered for SMS, (e.g. because of a removal of SMS subscription, CS location update, etc), the following procedure is applied.

Figure C.8.2-1: Cancellation of MME registration for SMS in MME

1. There is an event that shall trigger the cancellation of the MME being registered for SMS. This may for example be the removal of the SMS subscription for the UE, a CS location update, etc.

2. The HSS sends an Insert Subscriber Data Request (Remove SMS registration) message to the MME to inform the MME that it is no more registered for SMS in MME.

3. The MME sets its "MME Registered for SMS" parameter as not registered for SMS and the "SMS subscription data" is considered by the MME as invalid. It acknowledges with an Insert Subscriber Data Answer message to the HSS.

NOTE: A normal Cancel Location of MME which results in the MME no longer being registered for PS services for that UE will also render the MME not registered for SMS.

C.8.2.2 MME-initiated removal of registration of MME for SMS

When the MME needs to indicate to the HSS that it is no longer registered for SMS in HSS, (e.g. because the UE initiated a EPS attach only, TAU), the following procedure is applied.

Figure C.8.2-2: Removal of MME registration for SMS in HSS

1. There is an event that triggers the cancellation of the MME being registered for SMS. This may for example be an UE initiated EPS attach only or a TAU.

2. The MME sends a message to the HSS to inform the HSS to remove its registration for SMS in HSS.

3. The HSS cancels the SMS registration for the UE in the MME. It acknowledges and responds to the MME.

Annex D (informative):
Change history

Change history

Date

TSG #

TSG Doc.

CR

Rev

Cat

Subject/Comment

New

2010-06

SP-48

SP-100444

0218

4

B

CSFB triggered by LCS while UE is in active VoIP session

10.0.0

2010-09

SP-49

SP-100531

0596

A

Removing UE rejection on CLI for 1x MT call

10.1.0

2010-09

SP-49

SP-100531

0609

A

Correction to the paging issue for CS fallback capable UEs in NMO II or III

10.1.0

2010-09

SP-49

SP-100541

0575

1

A

Correction to Paging in MT CSFB

10.1.0

2010-09

SP-49

SP-100541

0577

1

A

CS domain access rights handling in CSFB

10.1.0

2010-09

SP-49

SP-100541

0585

1

A

Suspend clarification for CSFB

10.1.0

2010-09

SP-49

SP-100544

0580

3

B

eMPS CR for CSFB (reference, definition and overall description)

10.1.0

2010-09

SP-49

SP-100544

0581

2

B

eMPS CR for CSFB (attach procedure)

10.1.0

2010-09

SP-49

SP-100544

0582

2

B

eMPS CR for CSFB (Mobile Originating Call)

10.1.0

2010-09

SP-49

SP-100544

0583

2

B

eMPS CR for CSFB (Mobile Terminating Call)

10.1.0

2010-09

SP-49

SP-100544

0597

1

B

MPS Support for 1xCSFB – Intro and impacts to Network Elements

10.1.0

2010-09

SP-49

SP-100544

0598

1

B

MPS 1xCSFB impacts on MO and MT calls

10.1.0

2010-09

SP-49

SP-100558

0589

2

F

MSC reselection in case of roaming restriction

10.1.0

2010-09

SP-49

SP-100558

0599

2

C

Adding e1xCSFB support for dual Rx/Tx UE

10.1.0

2010-12

SP-50

SP-100681

0587

7

A

Multiple PLMNs selection in eNodeB

10.2.0

2010-12

SP-50

SP-100691

0591

2

F

Clarification of CSFB indication in Extended Service Request

10.2.0

2010-12

SP-50

SP-100691

0614

2

F

UE behaviour with ISR active after CSFB with suspended PS bearers

10.2.0

2010-12

SP-50

SP-100691

0618

6

C

Correction to CSFB MO flow

10.2.0

2010-12

SP-50

SP-100681

0620

1

A

Clarification on CSFB in idle mode

10.2.0

2010-12

SP-50

SP-100681

0622

2

A

Clarification on PLMN selection for CSFB

10.2.0

2010-12

SP-50

SP-100709

0629

1

F

MTC related NNSF in MME for SMS over SGs

10.2.0

2010-12

SP-50

SP-100681

0636

2

A

Correction to Abnormal Service Reject Procedure

10.2.0

2010-12

SP-50

SP-100681

0642

A

CSFB with Release with Redirection to UMTS and ‘deferred SIB reading’

10.2.0

2011-01

Update of LTE logo to LTE-Advanced logo

10.2.1

2011-03

SP-51

SP-110059

0643

A

Correction on CLI in page message for 1x MT call

10.3.0

2011-03

SP-51

SP-110064

0646

1

A

S102 Redirection Timing

10.3.0

2011-03

SP-51

SP-110076

0648

2

F

CS PLMN reselection requirement for CSFB and RAT/LA checking

10.3.0

2011-03

SP-51

SP-110064

0651

3

A

PS Suspending Clarification

10.3.0

2011-03

SP-51

SP-110064

0656

1

A

SMS-CSFB cell ID reporting correction

10.3.0

2011-03

SP-51

SP-110076

0660

1

F

Correction about the paging area in case of no available stored TAI list in MME

10.3.0

2011-03

SP-51

SP-110064

0663

1

A

3GPP2 alignment for 1xCSFB MT

10.3.0

2011-03

SP-51

SP-110076

0665

3

F

3GPP2 alignment for 1xCSFB SMS MT

10.3.0

2011-03

SP-51

SP-110064

0671

2

A

CSFB procedures for other types of CS services

10.3.0

2011-03

SP-51

SP-110064

0673

A

Correction to CSFB NACC/CCO

10.3.0

2011-03

SP-51

SP-110076

0674

3

B

Introduction of MT Roaming Forwarding for CSFB

10.3.0

2011-04

MCC Correction to History table version numbers

10.3.1

2011-06

SP-52

SP-110330

0658

5

F

Correction to CSFB procedure for UEs with LIPA PDN connections only

10.4.0

2011-06

SP-52

SP-110335

0666

3

F

Updating dual rx/tx e1xCSFB to use explicit UE support indicator

10.4.0

2011-06

SP-52

SP-110335

0681

2

F

RRC release with system information clarification

10.4.0

2011-06

SP-52

SP-110327

0684

4

F

Priority for terminating CSFB sessions for eMPS

10.4.0

2011-06

SP-52

SP-110330

0686

3

F

Interaction between LIPA and CSFB service

10.4.0

2011-06

SP-52

SP-110335

0689

F

Correct detach procedure with ISR activated

10.4.0

2011-06

SP-52

SP-110324

0691

A

Correction of PS suspension procedure in CSFB to GERAN A/Gb mode

10.4.0

2011-06

SP-52

SP-110324

0694

1

A

Correction of CSFB Paging to avoid the use of TMSI

10.4.0

2011-09

SP-53

SP-110456

0702

2

A

Clarification about suspend and resume handling

10.5.0

2011-12

SP-54

SP-110738

0706

4

F

Handling of SGs paging in VLR and MME failure cases

10.6.0

2011-12

SP-54

SP-110738

0709

2

F

VLR SGs paging retry

10.6.0

2011-12

SP-54

SP-110738

0710

3

F

Fast Return after CSFB

10.6.0

2011-12

SP-54

SP-110733

0714

1

A

Correction of CSFB Paging procedure in MME

10.6.0

2011-12

SP-54

SP-110733

0717

2

A

Separate LAU and RAU procedures in CS fallback procedure

10.6.0

2012-03

SP-55

SP-120068

0725

2

A

Clarification of LAU/RAU trigger for CSFB UE when ISR is activated

10.7.0

2012-03

SP-55

SP-120066

0722

1

A

Clarification of ISR activation condition for NMO II RAU and Periodic RAU

10.7.0

2012-03

SP-55

SP-120066

0750

1

A

Correction of system behaviour upon MME implicit detach timer expiry when SGs is associated and ISR is activated

10.7.0

2012-03

SP-55

SP-120075

0703

3

F

CM Service Request during MO-LR procedure

10.7.0

2012-03

SP-55

SP-120075

0736

1

F

Corrections to SGs paging for CSFB

10.7.0

2012-03

SP-55

SP-120088

0705

2

F

Clarification about ISR maintenance for CSFB

11.0.0

2012-03

SP-55

SP-120088

0727

1

F

Clarification of detach procedure when ISR is activated

11.0.0

2012-03

SP-55

SP-120088

0729

F

Correction of reference

11.0.0

2012-03

SP-55

SP-120088

0735

1

F

Clarification about PLMN selection for CS domain

11.0.0

2012-03

SP-55

SP-120086

0743

1

B

ISR deactivation exception for PS only SMS

11.0.0

2012-03

SP-55

SP-120086

0746

3

B

SMS over SGs usage to support NAS procedures for PS only SMS

11.0.0

2012-06

SP-56

SP-120239

0760

2

F

Clarifying the feature definition for SMS in MME

11.1.0

2012-06

SP-56

SP-120239

0761

7

F

Correction of SMS in MME related Cancellation Processes

11.1.0

2012-06

SP-56

SP-120240

0764

6

F

UE Availability for SMS

11.1.0

2012-06

SP-56

SP-120237

0766

1

A

Handling of SMS over SGs in case of absent LAI

11.1.0

2012-06

SP-56

SP-120237

0772

2

A

Correction for downlink unreachable due to wrong suspending

11.1.0

2012-06

SP-56

SP-120232

0793

2

A

Correction of system behaviour upon PGW initiated last PDP Context Deactivation when SGs is associated and ISR is activated

11.1.0

2012-06

SP-56

SP-120237

0795

4

A

Partial VLR failure or VLR restart with CSFB and ISR

11.1.0

2012-06

SP-56

SP-120246

0797

1

B

Taking UE support/non-support of GERAN network sharing into account in CSFB

11.1.0

2012-06

SP-56

SP-120240

0801

1

F

Update to SMS in MME Architecture reference points

11.1.0

2012-06

SP-56

SP-120251

0822

1

F

Alignment with stage 3 for the condition to deactivate ISR by the SGSN

11.1.0

2012-09

SP-57

SP-120486

0726

4

F

SGs Support for MSC in Pool to avoid dual VLR registration.

11.2.0

2012-09

SP-57

SP-120482

0809

3

F

Clarification on ISR and ‘SMS in MME’

11.2.0

2012-09

SP-57

SP-120482

0830

4

F

Correction of PS-only Feature Description

11.2.0

2012-09

SP-57

SP-120482

0834

1

F

SMS in MME consolidated description and updated scope

11.2.0

2012-09

SP-57

SP-120485

0836

C

Removing NMO-III

11.2.0

2012-12

SP-58

SP-120722

0810

6

F

Network sharing impact on the CSFB

11.3.0

2012-12

SP-58

SP-120717

0839

3

F

Registration of MME for SMS

11.3.0

2012-12

SP-58

SP-120713

0846

1

A

Suitable cell selected after CSFB

11.3.0

2013-03

SP-59

SP-130085

0848

F

Correction of when the MME shall send the CS domain operator to the VLR in case of network sharing

11.4.0

2013-03

SP-59

SP-130081

0850

A

Correction to enhanced CSFB to 1xRTT

11.4.0

2013-03

SP-59

SP-130080

0856

A

Priority setting for 1xCSFB correction

11.4.0

2013-06

SP-60

SP-130305

0847

3

F

Clarification on "SMS in MME"

11.5.0

2013-06

SP-60

SP-130241

0863

2

A

LAU-less Emergency call with CSFB

11.5.0

2013-06

SP-60

SP-130309

0868

2

F

Enabling terminating CS services for EPS/IMSI attached UE selecting a non-3GPP access

11.5.0

2013-06

SP-60

SP-130211

0871

4

A

CSFB interactions with IMS Emergency call

11.5.0

2013-06

SP-60

SP-130223

0872

3

F

Release of SGs association in case of SRVCC

11.5.0

2013-06

SP-60

SP-130224

0873

2

F

Handling of terminating CS services during IMS Call

11.5.0

2013-06

SP-60

SP-130320

0874

3

F

How CSFB UE return back to the former LTE PLMN

11.5.0

2013-06

SP-60

SP-130320

0875

2

F

Clarification for MME selection during NW-initiated CS Service procedure while UE is in IMS VoIP session

11.5.0

2013-06

SP-60

SP-130320

0877

2

F

CN signalling for allowing UE return to former LTE PLMN after CSFB

11.5.0

2013-06

SP-60

SP-130212

0879

1

A

MSC/VLR selection for MTC devices

11.5.0

2013-09

SP-61

SP-130370

0881

1

F

SMS in MME and SMS over IP

11.6.0

2013-09

SP-61

SP-130376

0882

1

F

Improve how CSFB UE return back to the former LTE PLMN

11.6.0

2013-09

SP-61

SP-130376

0883

2

D

Correction on 1xCSFB IMS interaction

11.6.0

2013-09

SP-61

SP-130376

0889

2

F

TMSI reallocation for CSFB/emergency handling with IMSI

11.6.0

2013-09

SP-61

SP-130368

0892

1

A

ISR with CSFB/ emergency handling with IMSI

11.6.0

2013-09

SP-61

SP-130376

0893

2

F

Corrections to UE return to last used LTE PLMN after CSFB

11.6.0

2013-09

SP-61

SP-130362

0880

3

F

Fix CSFB MT call failure due to HO

11.6.0

2013-09

SP-61

SP-130385

0885

2

C

Adding a recommendation on hysteresis mechanism for WORM feature

12.0.0

2013-12

SP-62

SP-130533

0861

7

C

Call Independent supplementary services with CSFB

12.1.0

2013-12

SP-62

SP-130525

0896

2

A

Earlier provision of the former last used LTE PLMN ID

12.1.0

2013-12

SP-62

SP-130525

0897

2

A

SS service ID used in the Paging message

12.1.0

2013-12

SP-62

SP-130522

0899

1

A

MME initiated removal of registration of MME for SMS

12.1.0

2013-12

SP-62

SP-130526

0900

2

F

Correction of the extended service request procedure for LIPA and SIPTO@LN

12.1.0

2013-12

SP-62

SP-130525

0901

A

Correction of resume procedure after CSFB

12.1.0

2013-12

SP-62

SP-130525

0903

1

A

CS MO indication to VLR via SGs

12.1.0

2013-12

SP-62

SP-130540

0907

2

F

Resuming PS services that have been handed over to non-3GPP

12.1.0

2014-03

SP-63

SP-140098

0918

A

Supporting priority services in 1xCSFB

12.2.0

2014-03

SP-63

SP-140111

0919

F

Correction of MT procedures in active mode

12.2.0

2014-06

SP-64

SP-140250

0925

3

A

Correction of CSFB priority and eMLPP handling

12.3.0

2014-06

SP-64

SP-140256

0927

1

A

How to transfer the last used LTE PLMN identity for CSFB to UTRAN

12.3.0

2014-06

SP-64

SP-140251

0930

1

A

Correction on priority paging

12.3.0

2014-06

SP-64

SP-140377

0931

1

F

New CSFB high priority indication for eMPS and emergency call

12.3.0

2014-06

SP-64

SP-140377

0932

F

Correction of ISR requirements for SGSN

12.3.0

2014-06

SP-64

SP-140252

0935

1

A

Handling CSFB request when VoLTE call is on-going in non SRVCC capable network/UE

12.3.0

2014-09

SP-65

SP-140425

0938

F

Corrections to message names

12.4.0

2015-03

SP-67

SP-150109

0941

2

F

Paging without LAI

12.5.0

2015-06

SP-68

SP-150224

0946

A

Correction of CSFB references for CS domain priority schemes

12.6.0

2015-06

SP-68

SP-150239

0939

6

C

Enable ISR for PS-only UE

13.0.0

2015-09

SP-69

SP-150501

0947

2

B

Mobile Terminating SMS handling for extended I-DRX

13.1.0

2015-12

SP-70

SP-150614

0953

2

F

Correction of references to parts of Detach procedures

13.2.0

2015-12

SP-70

SP-150611

0954

1

F

MT-SMS triggered Paging handling for extended DRX UE

13.2.0

2015-12

SP-70

SP-150614

0955

1

F

Correction on condition of CSFB MO

13.2.0

2016-03

SP-71

SP-160161

0961

1

B

SMS support with EPS attach and TAU

13.3.0

2016-06

SP-72

SP-160289

0956

4

B

MT SM retransmission by the SMS GMSC to a UE in eDRX at the time requested in the Delivery Report

13.4.0

2016-06

SP-72

SP-160289

0957

4

B

Prioritized SM retransmission by the SMS SC when the UE becomes reachable

13.4.0

2016-06

SP-72

SP-160289

0960

4

B

MT SM transmission to a UE in eDRX within the SM-Delivery-Start-Time/Timer

13.4.0

2016-06

SP-72

SP-160435

0964

2

F

Support for SMS using CP optimisation for CIOT

13.4.0

2016-06

SP-72

SP-160289

0956

4

B

MT SM retransmission by the SMS GMSC to a UE in eDRX at the time requested in the Delivery Report

13.4.0

2016-06

SP-72

SP-160289

0957

4

B

Prioritized SM retransmission by the SMS SC when the UE becomes reachable

13.4.0

2016-06

SP-72

SP-160289

0960

4

B

MT SM transmission to a UE in eDRX within the SM-Delivery-Start-Time/Timer

13.4.0

2016-06

SP-72

SP-160435

0964

2

F

Support for SMS using CP optimisation for CIOT

13.4.0

2017-03

Update to Rel-14 version (MCC)

14.0.0

2017-09

SP-77

SP-170714

0969

1

A

Alignment with stage 3 on handling of Mobile Terminating SMS handling for extended I-DRX

14.1.0

2017-09

SP-77

SP-170723

0970

2

F

Correction on combined attach for NB-IoT UE for TS 23.272 in R14

14.1.0

2017-12

SP-78

SP-170910

0972

2

A

Alignment with stage 3 of HLCOM aspect on Mobile Terminating SMS handling

14.2.0

2017-12

SP-78

SP-170724

0973

1

B

Introduction of Service Gap Control

15.0.0

2020-07

SP-88E

Update to Rel-16 version (MCC)

16.0.0

2021-09

SP-93E

SP-210932

0974

F

Reject Paging for CS domain paging

17.0.0