B.4 Signalling Scenarios (informative)

23.0663GPPRelease 17Stage 2Support of Mobile Number Portability (MNP)Technical realizationTS

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

This (informative) clause contains examples of signalling scenarios.

B.4.1 Delivery of SMS to a Non-ported Number – Direct Routeing – MNP-SRF acts as SCCP Relay

Figure B.4.1 shows the MNP-SRF operation for delivering an SMS message to a non-ported number.

Figure B.4.1: SRF operation for delivering an SMS message to a non-ported number where the SRI_for_SM message is submitted by a national interrogating network

1. The SMSC forwards a SM to the SMS-GMSC via a proprietary interface.

2. The SMS-GMSC generates a routeing enquiry for SM delivery. The MAP SRI_for_SM message is routed to the network’s MNP-SRF.

3. When MNP-SRFB receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being non-ported using information which may be retrieved from an NP database. The MNP-SRF function then populates the CdPA with an HLRB address. After modifying the CdPA, the message is routed to HLRB.

4. HLRB responds to the routeing enquiry by sending back an SRI_for_SM ack with the address of the VMSC.

5. The SMS-GMSC can now deliver the message to the VMSCB using a Forward_SMS message.

6. VMSCB further delivers the message to MSB.

B.4.2 Delivery of SMS to a Non-ported Number – Direct Routeing – MNP-SRF acts as Higher-level Relay

Figure B.4.2 shows the MNP-SRF operation for delivering an SMS message to a non-ported number where the SRI_for_SM message is submitted by a national interrogating network. For further details of the higher level relay function (e.g. TC relay), the reader is referred to [7].

Figure B.4.2: SRF operation for delivering an SMS message to a non-ported number where the SRI_for_SM message is submitted by a national interrogating network

1. The SMSC forwards a SM to the SMS-GMSC via a proprietary interface.

2. The SMS-GMSC generates a routeing enquiry for SM delivery. The MAP SRI_for_SM message is routed to the network’s MNP-SRF.

3. When MNP-SRFB receives the message it terminates the TCAP dialogue and an MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the TCAP portion of the message and identifies the MSISDN as being non-ported using information which may be retrieved from an NP database. The MNP-SRF function then initiates a new dialogue and routes the message to HLRB.

4. HLRB responds to the routeing enquiry by sending back an SRI_for_SM ack with the address of the VMSC.

5. MNP-SRFB responds to the routeing enquiry by sending back an SRI_for_SM ack with the address of the VMSC to the SMS-GMSCA.

6. The SMS-GMSC can now deliver the message to the VMSCB using a Forward_SMS message.

7. VMSCB further delivers the message to MSB.

B.4.3 Delivery of SMS to a Ported Number – Indirect Routeing

Figure B.4.3 shows the MNP-SRF operation for delivering an SMS message to a ported number where the interrogating network does not support direct routeing.

The message flows for this scenario are based on the use of an SCCP-relay function in the MNP-SRF(s). If the MNP-SRF(s) use(s) a higher-level relay function (e.g. TC-relay), then the response message will go via the MNP-SRF as shown in B.4.2. For further details of the signalling relay functions, the reader is referred to [7].

Figure B.4.3: SRF operation for delivering an SMS message to a ported number where the interrogating network does not support direct routeing

1. The SMSC forwards a SM to the SMS-GMSC via a proprietary interface.

2. The SMS-GMSC generates a routeing enquiry for SM delivery. The MAP SRI_for_SM message is routed to the number range holder network’s MNP-SRF.

3. When MNP-SRFB’ receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported using information which may be retrieved from an NP database. As the message is non-call related, the MNP-SRF function then populates the CdPA with either a routeing number or a concatenation of a routeing number and MSISDN. After modifying the CdPA, the message is routed to MNP-SRFB in the subscription network.

4. When MNP-SRFB receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported into the network using information which may be retrieved from an NP database. The MNP-SRF function then populates the CdPA with an HLRB address. After modifying the CdPA, the message is routed to HLRB.

5. HLRB responds to the routeing enquiry by sending back an SRI_for_SM ack with the address of the VMSC.

6. The SMS-GMSC can now deliver the message to the VMSCB using a Forward_SMS message.

7. VMSCB further delivers the message to MSB.

B.4.4 Delivery of SMS to a Ported Number – Direct Routeing

Figure B.4.4 shows the MNP-SRF operation for delivering an SMS message to a ported number where the interrogating network supports direct routeing.

The message flows for this scenario are based on the use of an SCCP-relay function in the MNP-SRFs. If the MNP-SRFs use a higher-level relay function (e.g. TC-relay), then the response message will go via the MNP-SRF as shown in B.4.2. For further details of the signalling relay functions, the reader is referred to [7].

Figure B.4.4: SRF operation for delivering an SMS message to a ported number where the interrogating network supports direct routeing

1. The SMSC forwards a SM to the SMS-GMSC via a proprietary interface.

2. The SMS-GMSC generates a routeing enquiry for SM delivery. The MAP SRI_for_SM message is routed to the network’s MNP-SRF.

3. When MNP-SRFA receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported using information which may be retrieved from an NP database. As the message is non-call related, the MNP-SRF function then populates the CdPA with either a routeing number or a concatenation of a routeing number and MSISDN. After modifying the CdPA, the message is routed to MNP-SRFB in the subscription network.

5. HLRB responds to the routeing enquiry by sending back an SRI_for_SM ack with the address of the VMSC.

6. The SMS-GMSC can now deliver the message to the VMSCB using a Forward_SMS message.

7. VMSCB further delivers the message to MSB.

B.4.5 International SOR for a Non-ported Number

Figure B.4.5 shows the MNP-SRF operation for optimally routeing an international call to a non-ported number.

The message flows for this scenario are based on the use of an SCCP-relay function in the MNP-SRF. If the MNP-SRF uses a higher-level relay function (e.g. TC-relay), then the response message will go via the MNP-SRF as shown in B.4.2. For further details of the signalling relay functions, the reader is referred to [7].

Figure B.4.5: SRF operation for optimally routeing an international call to a non-ported number

1. MSA originates a call to MSISDN.

2. VMSCA routes the call to the originating network’s GMSCA.

3. When GMSCA receives the ISUP IAM, it requests routeing information by submitting a MAP SRI with SOR parameter set to the number range holder network of the dialled MSISDN. Within the number range holder network, the message is routed to the network’s MNP-SRF.

4. When MNP-SRFB receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being non-ported using information which may be retrieved from an NP database. The MNP-SRF function then populates the CdPA with an HLRB address. After modifying the CdPA, the message is routed to HLRB.

5. When HLRB receives the SRI, it responds to the GMSCA by sending back an SRI ack with a MSRN.

6. GMSCA uses the MSRN to route the call to VMSCB.

7. VMSCB further establishes a traffic channel to MSB.

B.4.6 SOR for a Ported Number – Indirect Routeing

Figure B.4.6 shows the MNP-SRF operation for optimally routeing a call (using SOR) to a ported number where the interrogating network does not support direct routeing.

Figure B.4.6: MNP-SRF operation for optimally routeing a call (using SOR) to a ported number where the interrogating network does not support direct routeing

1. MSA originates a call to MSISDN.

2. VMSCA routes the call to the network’s GMSCA.

4. When MNP-SRFB’ receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported using information which may be retrieved from an NP database. As the message is non-call related, the MNP-SRF function then populates the CdPA with either a routeing number or a concatenation of a routeing number and MSISDN. After modifying the CdPA, the message is routed to MNP-SRFB in the subscription network.

5. When MNP-SRFB receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported into the network using information which may be retrieved from an NP database. The MNP-SRF function then populates the CdPA with an HLRB address. After modifying the CdPA, the message is routed to HLRB.

6. When HLRB receives the SRI, it responds to the GMSCA by sending back an SRI ack with a MSRN.

7. GMSCA uses the MSRN to route the call to VMSCB.

8. VMSCB further establishes a traffic channel to MSB.

B.4.7 Any Time Interrogation for a Ported Number – Indirect Routeing

Figure B.4.7 shows the MNP-SRF operation for routeing an Any_Time_Interrogation message for a ported number where the interrogating network does not support direct routeing.

Figure B.4.7: MNP-SRF operation for routeing an Any_Time_Interrogation message for a ported number where the interrogating network does not support direct routeing

1. The gsmSCF generates an Any_Time_Interrogation (ATI) message. The message is routed to the number range holder network’s MNP-SRF.

2. When MNP-SRFB’ receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported using information which may be retrieved from an NP database. As the message is non-call related, the MNP-SRF function then populates the CdPA with either a routeing number or a concatenation of a routeing number and MSISDN. After modifying the CdPA, the message is routed to MNP-SRFB in the subscription network.

3. When MNP-SRFB receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported into the network using information which may be retrieved from an NP database. The MNP-SRF function then populates the CdPA with an HLRB address. After modifying the CdPA, the message is routed to HLRB.

4. HLRB responds to the ATI by sending back an ATI ack with the requested information.

B.4.8 Any Time Interrogation for a Ported Number – Direct Routeing

Figure B.4.8 shows the MNP-SRF operation for routeing an Any_Time_Interrogation message for a ported number where the interrogating network supports direct routeing.

Figure B.4.8: MNP-SRF operation for routeing an Any_Time_Interrogation message for a ported number where the interrogating network supports direct routeing

1. The gsmSCF generates an Any_Time_Interrogation (ATI) message. The message is routed to the network’s MNP-SRF.

2. When MNP-SRFB receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported into the network using information which may be retrieved from an NP database. The MNP-SRF function then populates the CdPA with an HLRB address. After modifying the CdPA, the message is routed to HLRB.

3. HLRB responds to the ATI by sending back an ATI ack with the requested information.

B.4.9 CCBS where the Busy Subscriber is a Ported Subscriber ‑ Direct Routeing

Figure B.4.9 shows the MNP-SRF operation for routeing a CCBS Request for a ported number where the interrogating network supports direct routeing.

Figure B.4.9: MNP-SRF operation for routeing a CCBS Request for a ported number where the interrogating network supports direct routeing

1. The VMSCA receives a ISUP Release message with cause value ‘subscriber busy’ from VMSCB.

2. VLRA/VMSCA sends a Register_CC_Entry to HLRA using the HLRA address as CdPA on SCCP.

3. The HLRA sends a CCBS Request message to the networks MNP-SRFA.

4. When MNP-SRFA receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies the MSISDN as being ported using information which may be retrieved from an NP database. As the message is non-call related, the MNP-SRF function then populates the CdPA with either a routeing number or a concatenation of a routeing number and MSISDN. After modifying the CdPA, the message is routed to MNP-SRFB in the subscription network.

6. HLRB can now respond to HLRA by sending back a CCBS ack message.

B.4.10 Calling Name Presentation Flows – MNP-SRF acts as SCCP Relay

Figure B.4.10 shows the MNP-SRF operation for delivering an CNAP message to an ANSI Calling Name Database.

Figure B.4.10: SRF operation for delivering an CNAP message to the CNDB

1. An incoming call ( an Initial Address message with Generic Name parameter set to "presentation allowed" is received at a MSC. The MSC inteerogates the VLR to determine if the called party is subscribed to the CNAP service. The VLR Response indicates that the called party is subscribed to CNAP;

2. The MSC generates a TCAP message "Query With Permission". The Query With Permission message is routed to the network’s MNP-SRF;

3. When MNP-SRFB receives the message, MNP-SRF operation is triggered. The MNP-SRF functionality analyses the MSISDN in the CdPA and identifies which CNDB the MSISDN is populated using information which may be retrieved from an NP database. The MNP-SRF function then populates the CdPA with an CNDB address. After modifying the CdPA, the message is routed to CNDB;

4. CNDB responds to the routeing enquiry by sending back a Query With Permission ack with the address of the MSC. The MSC can now deliver the Calling Name to the terminating subscriber .

Annex C (normative):
MNP Signalling Relay Function – Call Related Signalling