A.1 Architecture

03.663GPPStage 2Support of GSM Mobile Number Portability (MNP)TS

A.1.1 Network Options

The following network operator options are defined for the MT calls in the GMSC:

  • Terminating call Query on Digit Analysis (TQoD);
  • Query on HLR Release (QoHR).

In a GSM network which supports the IN-based approach for call related MNP, each GMSC shall support at least one of these options.

The following network operator option is defined for MO calls in VMSCA and for forwarded calls in the GMSC and VMSCB:

  • Originating call Query on Digit Analysis (OQoD).

In a GSM network which supports the IN-based approach for call related MNP, it is a network operator decision, taking into account the regulatory and architectural constraints that may prevail, whether or not VMSCs and GMSCs support this option.

The use of OQoD in transit switches in a PLMN while avoiding multiple database interrogations is for further study.

The interworking between the CCF and the SSF for MNP is for further study.

Note that for different number ranges different options may be chosen.

A.1.2 No NP Query required – Number is not subject for portability

Figure A.1.2 shows the architecture for a call to a number that is not subject for portability. This can be for several reasons like for example:

– the national regulator has stipulated some number series as being non-portable or;

– in an initial phase only a limited amount of subscribers might port in certain number blocks and some operators might want to treat the call routeing according to traditional routeing plans without any change.

Figure A.1.2: Call to a non-ported number, no NP query required

1 From an Originating Exchange a call is set up to MSISDN. The call is routed to the Number range holder network being the Subscription network;

2 When GMSCB receives the ISUP IAM, it requests routeing information by submitting a MAP SRI to the HLRB including the MSISDN in the request;

3 The HLRB requests an MSRN from the MSC/VLRB where the mobile subscriber currently is registered;

4 The MSC/VLRB returns an MSRN back to the HLRB;

5 The HLRB responds to the GMSCB by sending an SRI ack with an MSRN;

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

A.1.3 NP Query in Number Range Holder Network

A.1.3.1 TQoD – Number is not ported

Figure A.1.3.1 shows the architecture for a call where the Originating network has no knowledge whether the MSISDN is ported or not and uses the traditional routeing plans for routeing the call to the Number range holder network for further routeing decisions.

Figure A.1.3.1: Call to a non-ported number using TQoD procedure

  1. From an Originating Exchange a call is set up to MSISDN. The call is routed to the Number range holder network being the Subscription network;
  2. When GMSCB receives the ISUP IAM, it will send a database query to the NPDB as a result of analysis of the received MSISDN. The MSISDN is included in the query to the NPDB;
  3. The NPDB detects that the MSISDN is not ported and responds back to the GMSCB to continue the normal call setup procedure for MT calls;
  4. The GMSCB requests routeing information by submitting a MAP SRI to the HLRB, including the MSISDN in the request;
  5. The HLRB requests an MSRN from the MSC/VLRB where the mobile subscriber owning the MSISDN currently is registered;
  6. The MSC/VLRB returns an MSRN back to the HLRB;
  7. The HLRB responds to the GMSCB by sending an SRI ack with an MSRN;
  8. GMSCB uses the MSRN to route the call to VMSCB.

Note that the NPDB may be outside the number range holder network if a shared NPDB is used.

A.1.3.2 TQoD – Number is ported

Figure A.1.3.2 shows the architecture for a call where the Originating network has no knowledge whether the MSISDN is ported or not and uses the traditional routeing plans for routeing the call to the Number range holder network for further routeing decisions.

Figure A.1.3.2: Call to a ported number using TQoD procedure

  1. From an Originating Exchange a call is set up to MSISDN. The call is routed to the Number range holder network;
  2. When GMSCA receives the ISUP IAM, it will send a database query, including the MSISDN, to the NPDB as a result of analysis of the received MSISDN;
  3. The NPDB detects that the MSISDN is ported and responds back to the GMSCA with a Routeing Number pointing out the Subscription network;
  4. The call is routed to the Subscription network based on the Routeing Number carried in ISUP IAM message; also the MSISDN is included in IAM.
  5. The GMSCB requests routeing information by submitting a MAP SRI to the HLRB, including the MSISDN in the request. The capability to route messages to the correct HLR is required.
  6. The HLRB requests an MSRN from the MSC/VLRB where the mobile subscriber currently is registered;
  7. The MSC/VLRB returns an MSRN back to the HLRB;
  8. The HLRB responds to the GMSCB by sending an SRI ack with an MSRN;
  9. GMSCB uses the MSRN to route the call to VMSCB.

Note that the NPDB may be outside the number range holder network if a shared NPDB is used.

A.1.3.3 QoHR – Number is ported

Figure A.1.3.3 shows the architecture for a call where the Originating network has no knowledge whether the MSISDN is ported or not and uses the traditional routeing plans for routeing the call to the Number range holder network for further routeing decisions.

Figure A.1.3.3: Call to a ported number using QoHR procedure

  1. From an Originating Exchange a call is set up to MSISDN. The call is routed to the number range holder network;
  2. When GMSCA receives the ISUP IAM, it requests routeing information by submitting a MAP SRI to the HLRA including the MSISDN in the request;
  3. The HLRA returns a MAP SRI ack with an "Unknown Subscriber" error since no record was found for the subscriber in the HLRA;
  4. When GMSCA receives the error indication form the HLRA, this will trigger the sending of a database query to the NPDB, including the MSISDN in the query;
  5. The NPDB detects that the MSISDN is ported and responds back to the GMSCA with a Routeing Number pointing out the Subscription network;
  6. The call is routed to the Subscription network based on the Routeing Number carried in ISUP IAM message; also the MSISDN is included in IAM.
  7. The GMSCB requests routeing information by submitting a MAP SRI to the HLRB, including the MSISDN in the request. The capability to route messages to the correct HLR is required.
  8. The HLRB requests an MSRN from the MSC/VLRB where the mobile subscriber currently is registered;
  9. The MSC/VLRB returns an MSRN back to the HLRB;
  10. The HLRB responds to the GMSCB by sending an SRI ack with an MSRN;
  11. GMSCB uses the MSRN to route the call to VMSCB.

Note that the NPDB may be outside the number range holder network if a shared NPDB is used.

A.1.4 NP Query in Originating Network

A.1.4.1 OQoD – Number is not ported

Figure A.1.4.1 shows the architecture for a call where already the Originating network has the knowledge whether the MSISDN is ported or not and can route the call directly to the Subscription network that in this case is the same as the Number range holder network.

Figure A.1.4.1: Call to a non-ported number using OQoD procedure

  1. A call is initiated by Mobile Subscriber A towards Mobile Subscriber B, using MSISDN of the called subscriber;
  2. When VMSCA receives the call setup indication, it will send a database query to the NPDB as a result of analysis of the received MSISDN, including the MSISDN in the query;
  3. The NPDB detects that the MSISDN is not ported and responds back to the VMSCA to continue the normal call setup procedure for MO calls. Depending on database configuration option, the NPDB could either return a Routeing Number on not ported calls, as done for ported calls, or the call is further routed using the MSISDN number only towards the Number range holder network;
  4. The call is routed to the Number range holder/Subscription network based on the MSISDN or Routeing Number carried in ISUP IAM message;
  5. The GMSCB requests routeing information by submitting a MAP SRI to the HLRB, including the MSISDN in the request;
  6. The HLRB requests an MSRN from the MSC/VLRB where the mobile subscriber currently is registered;
  7. The MSC/VLRB returns an MSRN back to the HLRB;
  8. The HLRB responds to the GMSCB by sending an SRI ack with an MSRN;
  9. GMSCB uses the MSRN to route the call to VMSCB.

Note that the NPDB may be outside the national originating network if a shared NPDB is used.

A.1.4.2 OQoD – Number is ported

Figure A.1.4.2 shows the architecture for a call where already the Originating network has the knowledge that the MSISDN is ported and can route the call directly to the Subscription network without involving the Number range holder network.

Figure A.1.4.2: Call to a ported number using OQoD procedure

  1. A call is initiated by Mobile Subscriber A towards Mobile Subscriber B, using MSISDN of the called subscriber;
  2. When VMSCA receives the call setup indication, it will send a database query to the NPDB as a result of analysis of the received MSISDN including the MSISDN in the query;
  3. The NPDB detects that the MSISDN is ported and responds back to the VMSCA with a Routeing Number pointing out the Subscription network;
  4. The call is routed to the Subscription network based on the Routeing Number carried in ISUP IAM message; also the MSISDN is included in IAM.
  5. The GMSCB requests routeing information by submitting a MAP SRI to the HLRB, including the MSISDN in the request. The capability to route messages to the correct HLR is required.
  6. The HLRB requests an MSRN from the MSC/VLRB where the mobile subscriber currently is registered;
  7. The MSC/VLRB returns an MSRN back to the HLRB;
  8. The HLRB responds to the GMSCB by sending an SRI ack with an MSRN;
  9. GMSCB uses the MSRN to route the call to VMSCB.

Note that the NPDB may be outside the national originating network if a shared NPDB is used.