6 Procedures and information flows for PN redirection

23.2593GPPPersonal Network Management (PNM)Procedures and information flowsRelease 17Stage 2TS

6.1 Procedures and information flows in the IP CN subsystem

6.1.1 General

One of the functionalities enabled by the PNM AS in the IM CN subsystem is called PNUE redirection that redirects sessions destined for any UEs of a PN to the default UE of the same PN as described in 3GPP TS 22.259 [1]. The PN UE redirection applies only to the initial request for a UE-terminating call. The procedures for supporting the PN UE redirection in the IM CN subsystem take advantage of the interface between an S-CSCF and an AS in the IM CN subsystem described in 3GPP TS 23.002 [2] and the procedures described in 3GPP TS 23.218 [3].

When receiving an initial request for a UE-terminating call, the S-CSCF performs the procedure defined in 3GPP TS 23.218 [3] to route the initial request for the UE-terminating call to the PNM AS based on matching of initial filter criteria before performing any other routing procedures to the terminating UE. The PNM AS then executes the redirection of the initial request to the default UE of the PN based on the PN-user’s PN configuration as described in clause 6. The redirection of the initial request for the UE-terminating call can be executed either on an IP multimedia application basis or on the media component(s) of an IP multimedia application basis supported by the terminating UE capabilities and the PN-user subscriptions.

If the PN-user configured a UE list of different priorities for the PN UE redirection, the PNM AS shall execute the session redirection for a particular UE based on the configuration in a decreasing order of the priority. If the session redirection for a UE of a higher priority fails, the PNM AS shall perform the PNM session redirection for the other UE of the next lower priority.

6.1.2 Procedures and information flows for PN UE redirection in the IM CN subsystem

Figure 6.1.2-1 describes the procedures and information flows for handling the PN UE redirection in the IM CN subsystem. Without loss of generality, it is assumed for figure 6.2.1-1 that a PN-user’s PN consists of two UEs, i.e., the UE-1 and the UE-2. The UE-2 is the default UE according to PN-user’s PN configuration as described in clause 6. Furthermore, it is assumed that the two UEs have different public user identities.

Figure 6.1.2-1: Initial request to UE-1 and redirected to UE-2 by the PNM AS in the IM CN subsystem

1. An initial request to the UE-1 containing the Request-URI of the UE-1 public user identity arrives at the S-CSCF #1.

2. The S-CSCF #1 determines that the initial request is for a UE-terminated case, invokes the termination service control logic required for the UE-1 and evaluates the initial filter criteria, which results in re-routing the initial request to the PNM AS.

3. As a result of the termination service control logic invocation for the UE-1, the S-CSCF #1 forwards the initial request to the PNM AS.

4. The PNM AS executes the PN UE redirection control logic based on the PN-user’s PN configurations as described in clause 6. The PNM AS decides to redirect the initial request to the default UE of the PN, i.e., to the UE-2.

5. As a result of the PN UE redirection control logic execution, the PNM AS sends the redirected initial request containing the Request-URI of the UE-2 public user identity to the S-CSCF #1.

6. The S-CSCF #1 treats the redirected initial request as a UE-originated case, and forwards the redirected initial request to the S-CSCF #2. The S-CSCF #1 and the S-CSCF #2 can be the same entity.

7. The S-CSCF #2 treats the redirected initial request as a UE-terminated case, invokes the termination service control logic required for the UE-2 and evaluates the initial filter criteria, which may results in re-routing the redirected initial request to the other ASs.

8-10. The S-CSCF #2 forwards the redirected request to the PNM AS as the result of the termination service control logic for the UE-2. The PNM AS executes the PN UE redirection control logic and decides to forward the request as the UE-2 is the default UE of the PN.

11. The S-CSCF#2 continues the redirected initial request based on the standard call setup procedures as described in 3GPP TS 23.228 [4].

Figure 6.1.2-2 describes the procedures and information flows for handling the PN UE redirection in the IM CN subsystem when the default UE (in this example the UE-2) in the PN shares the same public user identity with the UE-1.

NOTE: It’s assumed that the UE-2 can support GRUU.

Figure 6.1.2-2: Initial request to UE-1 and redirected to UE-2 by the PNM AS in the IM CN subsystem when the UE-2 shares the same public user identity with the UE-1

1. An initial request to the UE-1 containing the Request-URI of the UE-1 public user identity arrives at the S-CSCF.

2. The S-CSCF determines that the initial request is for a UE-terminated case, invokes the termination service control logic required for the UE-1 and evaluates the initial filter criteria, which results in re-routing the initial request to the PNM AS.

3. As a result of the termination service control logic invocation for the UE-1, the S-CSCF forwards the initial request to the PNM AS.

4. The PNM AS executes the PNM redirection service control logic based on the User’s PN configurations as described in clause 6. The PNM AS decides to redirect the initial request to the default UE of the PN, i.e., to the UE-2.

5. As a result of the PNM redirection service logic execution, the PNM AS sends the redirected initial request containing the Request-URI which is set to the GRUU of the UE-2 to the S-CSCF.

6. The S-CSCF continues the redirected initial request procedure based on the standard call setup procedures as described in 3GPP TS 23.228 [4].

Figure 6.1.2-3 describes the procedures and information flows for handling the PN UE redirection in the IM CN subsystem when the default UE (in this example the UE-2) in the PN cannot setup the session. Consequently, the PNM AS performs the PNM session redirection for the other UE of the next lower priority (in this example the UE-3).

Figure 6.1.2-3: Initial request to UE-1 and redirected to UE-3 by the PNM AS in the IM CN subsystem when the initial request to UE-2 fails

1. An initial request to the UE-1 containing the Request-URI of the UE-1 public user identity arrives at the S-CSCF #1.

2. The S-CSCF #1 determines that the initial request is for a UE-terminated case, invokes the termination service control logic required for the UE-1 and evaluates the initial filter criteria, which results in re-routing the initial request to the PNM AS.

3. As a result of the termination service control logic invocation for the UE-1, the S-CSCF #1 forwards the initial request to the PNM AS.

4. The PNM AS executes the PN UE redirection control logic based on the PN-user’s PN configurations as described in clause 6. The PNM AS decides to redirect the initial request to the default UE of the PN, i.e., to the UE-2.

5. As a result of the PN UE redirection control logic execution, the PNM AS sends the redirected initial request containing the Request-URI of the UE-2 public user identity to the S-CSCF #1.

6. The S-CSCF #1 treats the redirected initial request as a UE-originated case, and forwards the redirected initial request to the S-CSCF #2. The S-CSCF #1 and the S-CSCF #2 can be the same entity.

7. The S-CSCF #2 treats the redirected initial request as a UE-terminated case, invokes the termination service control logic required for the UE-2 and evaluates the initial filter criteria, which may results in re-routing the redirected initial request to the other ASs.

8-10. The S-CSCF #2 forwards the redirected request to the PNM AS as the result of the termination service control logic for the UE-2. The PNM AS executes the PN UE redirection control logic and decides to forward the request as the UE-2 is the default UE of the PN.

11. The S-CSCF#2 continues the redirected initial request which is forwarded to UE-2.

12-13. UE-2 cannot setup the session and returns an error response back to PNM AS.

14. The PNM AS executes the PN UE redirection control logic for the other UE of the next lower priority which in this example is UE-3.

15-16. As a result of the PN UE redirection control logic execution, the PNM AS forwards the redirected initial request containing the Request-URI of the UE-3 public user identity to the UE-3.

6.1.3 Procedures and information flows for PNE redirection in the IM CN subsystem

Figure 6.1.3-1 describes the procedures and information flows for handling the PNE redirection in the IM CN subsystem. Without loss of generality, it is assumed for figure 6.1.3-1 that a PN-user’s PN consists of three PNEs, i.e., the UE-1, the UE-2 and PNE-1.UE-2 and PNE-1 belong to a PAN. The PNE-1 is the default PNE according to PN-user’s PN configuration as described in clause 6. Furthermore, it is assumed that the two UEs have different public user identities.

Figure 6.1.3-1: Initial request to UE-1 and redirected to PNE-1 by the PNM AS in the IM CN subsystem

1. An initial request to the UE-1 containing the Request-URI of the UE-1 public user identity arrives at the S-CSCF #1.

2. The S-CSCF #1 determines that the initial request is for a UE-terminated case, invokes the termination service control logic required for the UE-1 and evaluates the initial filter criteria, which results in re-routing the initial request to the PNM AS.

3. As a result of the termination service control logic invocation for the UE-1, the S-CSCF #1 forwards the initial request to the PNM AS.

4. The PNM AS executes the PNE redirection control logic based on the PN-user’s PN configurations as described in clause 6. The PNM AS decides to redirect the initial request to the default UE of the PN, i.e., to the PNE-1.

5. As a result of the PNE redirection control logic execution, the PNM AS sends the redirected initial request containing the Request-URI of the GRUU of UE-2 and the identity of PNE-1 to the S-CSCF #1.

6. The S-CSCF #1 treats the redirected initial request as a UE-originated case, and forwards the redirected initial request to the S-CSCF #2. The S-CSCF #1 and the S-CSCF #2 can be the same entity.

7. The S-CSCF #2 treats the redirected initial request as a UE-terminated case, invokes the termination service control logic required for the UE-2 and evaluates the initial filter criteria, which can result in re-routing the redirected initial request to the other ASs.

8-10. The S-CSCF #2 forwards the redirected request to the PNM AS as the result of the termination service control logic for the UE-2. The PNM AS executes the PN UE redirection control logic and decides to forward the request as the PNE-1 is the default UE of the PN.

11. The S-CSCF#2 forwards the initial request including identity of PNE-1 to the UE-2.

12. The UE-2 forwards the initial request to the PNE-1 via the PAN internal interface.

6.2 Procedures and information flows in the CS domain

6.2.1 General

Similar to the functionality described in the subclause 6.1.1, the gsmSCF (CAMEL service for PNM) can redirect calls destined for any UEs of a PN in the CS domain to the default UE of the same PN. The procedures for supporting the PNM call redirection in the CS domain takes advantage of the interface between a GMSC and a gsmSCF in the CS domain described in 3GPP TS 23.078 [8] and the procedures described in 3GPP TS 23.018 [10].

When receiving a call request for a UE in the PN, the GMSC performs the procedure defined in 3GPP TS 23.078 [8] to route the request to the gsmSCF (CAMEL service for PNM) based on the T_CSI configured to the UE before performing any other routing procedures to the terminating UE. The gsmSCF (CAMEL service for PNM) then executes the redirection of the request based on the PN-user’s PN configuration as described in clause 6.

If the PN-user configured a UE list of different priorities for the PNM call redirection, the gsmSCF (CAMEL service for PNM) shall execute the call redirection for a particular UE based on the configuration in a decreasing order of the priority. If the call redirection for a UE of a higher priority fails, the gsmSCF (CAMEL service for PNM) shall perform the PNM call redirection for the other UE of the next lower priority.

6.2.2 Procedures and information flows for PN UE redirection in the CS domain

Figure 6.2.2-1 describes the procedures and information flows for handling the PNM call redirection in the CS domain. Without loss of generality, it is assumed for figure 6.2.2-1 that a PN-user’s PN consists of two UEs, i.e., the UE-1 and the UE-2. The UE-2 is the default UE according to PN-user’s PN configuration as described in clause 6.

Figure 6.2.2-1: Initial request to UE-1 and redirected to UE-2 by the gsmSCF (CAMEL service for PNM) in the CS domain

1. A call request to the UE-1 containing the MSISDN of the UE-1 as the called party number arrives at the GMSC #1.

2. On receipt of the incoming call request, the GMSC#1 queries the HSS for routing information.

3. The HSS provides information including the T-CSI information element that contains information configured for the PNM subscriber, identifying the subscriber as having terminating CAMEL services.

4. The HSS returns the T-CSI information element to the GMSC#1 in response to the query for routing information (SRI).

5. The GMSC#1 triggers a CAMEL activity which results in sending a CAMEL IDP message to the GSM Service Control Function (gsmSCF).

6. The gsmSCF (CAMEL service for PNM) executes the PN UE redirection control logic based on the PN-user’s PN configurations as described in clause 6. The gsmSCF (CAMEL service for PNM) decides to redirect the call request to the default UE of the PN, i.e., to the UE-2.

7. As a result of the PN UE redirection control logic execution, the gsmSCF (CAMEL service for PNM) to respond to the CAMEL IDP message with a CAMEL CONNECT message containing the MSISDN of the UE-2 as the called party number.

8. The GMSC#1 initiates the CS call towards the GMSC#2 by sending an Initial Setup Message (e.g. ISUP IAM, BICC IAM, and SIP-I Invite).

9-13. The GMSC#2 queries the HSS for routing information and triggers a CAMEL activity to the gsmSCF. The gsmSCF executed the PNM redirection service control logic and decides to forward the request as the UE-2 is the default UE of the PN, so it responds with a CMAEL CONTINUE message to the GMSC#2.

14. The GMSC#2 continues the redirected call request based on the standard call setup procedures as described in 3GPP TS 23.018 [10].

Figure 6.2.2-2 describes the procedures and information flows for handling the PN UE redirection in the CS domain when the default UE (in this example the UE-2) in the PN cannot setup the session. Consequently, the gsmSCF performs the PNM session redirection for the other UE of the next lower priority (in this example the UE-3).

Figure 6.2.2-2: Initial request to UE-1 and redirected to UE-3 by the gsmSCF (CAMEL service for PNM) in the CS domain when the initial request to UE-2 fails

1. A call request to the UE-1 containing the MSISDN of the UE-1 as the called party number arrives at the GMSC #1.

2. On receipt of the incoming call request, the GMSC#1 queries the HSS for routing information.

3. The HSS provides information including the T-CSI information element that contains information configured for the PNM subscriber, identifying the subscriber as having terminating CAMEL services.

4. The HSS returns the T-CSI information element to the GMSC#1 in response to the query for routing information (SRI).

5. The GMSC#1 triggers a CAMEL activity which results in sending a CAMEL IDP message to the GSM Service Control Function (gsmSCF).

6. The gsmSCF (CAMEL service for PNM) executes the PN UE redirection control logic based on the PN-user’s PN configurations as described in clause 6. The gsmSCF (CAMEL service for PNM) decides to redirect the call request to the default UE of the PN, i.e., to the UE-2.

7. As a result of the PN UE redirection control logic execution, the gsmSCF (CAMEL service for PNM) to respond to the CAMEL IDP message with a CAMEL CONNECT message containing the MSISDN of the UE-2 as the called party number.

8. The GMSC#1 initiates the CS call towards the GMSC#2 by sending an Initial Setup Message (e.g. ISUP IAM, BICC IAM, and SIP-I Invite).

9-13. The GMSC#2 queries the HSS for routing information and triggers a CAMEL activity to the gsmSCF. The gsmSCF executed the PNM redirection service control logic and decides to forward the request as the UE-2 is the default UE of the PN, so it responds with a CMAEL CONTINUE message to the GMSC#2.

14. The GMSC#2 continues the redirected call request based on the standard call setup procedures as described in 3GPP TS 23.018 [10].

15. UE-2 cannot setup the session and generates an error response.

16. GMSC#2 sends the EventReportBCSM message to the gsmSCF.

17. The gsmSCF executes the PN UE redirection control logic for the other UE of the next lower priority which in this example is UE-3.

18-19. As a result of the PN UE redirection control logic execution, the gsmSCF forwards the redirected initial request containing the MSISDN of the UE-3 as the called party number to the UE-3.

6.3 Procedures and information flows in the domain interworking

6.3.1 General

After the PNM AS executes the redirection of the initial request based on the PN-user’s PN configuration, the initial request could be routed to different domain, i.e. from IM CN subsystem to CS domain or from CS domain to IM CN subsystem.

The procedures for supporting the interworking between IM CN subsystem and CS domain in the PNM session redirection take advantage of the procedures specified in 3GPP TS 23.228 [4].

NOTE: If the UE-2 is attached both in the CS domain and the IM CN subsystem, how the PNM AS selects the particular domain for the PN UE redirection is out of the scope of this document.

6.3.2 Procedures and information flows for PN UE redirection from IM CN subsystem to CS domain

Figure 6.3.2-1 describes the procedures and information flows for handling the PNM Session redirection from IM CN subsystem to CS domain. Without loss of generality, it is assumed for figure 6.3.2-1 that a PN-user’s PN consists of two UEs, i.e., the UE-1 and UE-2 and the UE-2 attached in CS domain doesn’t have the subscription to IMS is the default UE according to PN-user’s PN configuration as described in clause 6.

Figure 6.3.2-1: Initial request in IM CN subsystem and redirected to UE-2 in CS domain by the PNM AS

1. An initial request destined to the UE-1 containing the Request-URI of the UE-1 public user identity arrives at the S-CSCF.

2. The S-CSCF determines that the initial request if for a UE-terminated case, invokes the termination service control logic required for the UE-1 and evaluates the initial filter criteria, which results in re-routing the initial request to the PNM AS.

3. As a result of the termination service control logic invocation for the UE-1, the S-CSCF forwards the initial request to the PNM AS.

4. The PNM AS executes the PN UE redirection control logic based on the PN-user’s PN configurations as described in clause 6. The PNM AS decides to redirect the initial request to the default UE of the PN, i.e., to the UE-2 which in this example can be found in the CS domain only.

5. As a result of the PN UE redirection control logic execution, the PNM AS sends the redirected initial request containing the Request-URI of the UE-2 public user identity to the S-CSCF.

6. The S-CSCF treats the redirected request as a UE-originated case and performs the domain transit procedure specified in 3GPP TS 23.228 [4]. Eventually, the session initiation arrives to an MGCF.

7. The MGCF sends an IAM message containing the MSISDN of the UE-2 as the called party number towards GMSC.

8. The GMSC continues the redirected call request based on the standard call setup procedures as described in 3GPP TS 23.018 [10].

6.3.3 Procedures and information flows for PN UE redirection from CS domain to IM CN subsystem

Figure 6.3.3-1 describes the procedures and information flows for handling the PN UE redirection from CS domain to IM CN subsystem. Without loss of generality, it is assumed for figure 6.3.3-1 that a PN-user’s PN consists of two UEs, i.e., the UE-1 and UE-2 and the UE-2 registered only in IM CN subsystem is the default UE according to PN-user’s PN configuration as described in clause 6.

Figure 6.3.3-1: Initial request in CS domain and redirected to UE-2 in IM CN subsystem by the gsmSCF

1. A call request to the UE-1 containing the MSISDN of the UE-1 as the called party number arrives at the GMSC.

2. On receipt of the incoming call request, the GMSC queries the HSS for routing information.

3. The HSS returns the T-CSI information element that contains information configured for the PNM subscriber to the GMSC#1 in response to the query for routing information (SRI).

4. The GMSC triggers a CAMEL activity which results in sending a CAMEL IDP message to the gsmSCF (CAMEL service for PNM).

5. The gsmSCF (CAMEL service for PNM) executes the PN UE redirection control logic based on the PN-user’s PN configurations as described in clause 6. The gsmSCF (CAMEL service for PNM) decides to redirect the call request to the default UE of the PN, i.e., to the UE-2 which in this example can be found in IM CN subsystem only.

6. As a result of the PN UE redirection control logic execution, the gsmSCF (CAMEL service for PNM) responds to the CAMEL IDP message with a CAMEL CONNECT message containing the MSISDN of the UE-2 as the called party number.

7. The GMSC initiates the call to the MGCF with an IAM message containing the MSISDN of UE-2 as the called party number.

8. The MGCF initiates a SIP INVITE request with the request URI of UE-2 public user identity towards the S-CSCF.

9. The S-CSCF continues the redirected initial request based on the standard call setup procedures as described in 3GPP TS 23.228 [4].