14 Proxy Mobile IPv6 EPC Restoration Procedure

29.2753GPPProxy Mobile IPv6 (PMIPv6) based Mobility and Tunnelling protocolsRelease 17Stage 3TS

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

14.1 PGW triggered SGW restoration procedure

14.1.1 General

The PGW triggered SGW restoration procedure is specified in 3GPP TS 23.007 [13]. The Proxy Mobile IPv6 LMA Initiated Update Notification procedure specified in subclause 5.11 is used to initiate the PGW triggered SGW restoration procedure.

14.1.2 Serving GW procedures

The Serving GW shall follow the PGW triggered SGW restoration procedure as specified in subclause 27.2.3.3 of 3GPP TS 23.007 [13]. When receiving the Update Notification message with notification reason "PGW Downlink Trigger Notification", the Serving GW shall response with an Update Notification Acknowledgement message specified as the MAG procedure in subclause 5.11.

14.1.3 PDN GW procedures

The PDN GW shall follow the PGW triggered SGW restoration procedure as specified in subclause 27.2.3.4 and 20.2.7.1 of 3GPP TS 23.007 [13]. When sending the Update Notification message, the PDN GW shall follow the LMA procedure specified in subclause 5.11 as follows:

1. The notification reason shall be set to "PGW Downlink Trigger Notification".

Editor’s Note: The Notification reason "PGW Downlink Trigger Notification " needs to be registered in IANA.

2. If the MME/S4-SGSN identifier was received in the last Create Session Request or Modify Bearer Request message as specified in 3GPP TS 23.007 [13], the MME/SGSN Identifier mobility option shall contain the stored MME/S4-SGSN identifier.

3. If the restoration procedure is caused by S5 path failure as specified in subclause 20.2.7.1 of 3GPP TS 23.007 [13], the Update Notification Message shall contain the PDN GW IP Address and GRE key option which shall contain the PGW IP address and uplink GRE key for control plane for the PDN connection.

14.2 Update PDP context/Bearer at P-CSCF failure

14.2.1 General

The update PDP context/Bearer at P-CSCF failure procedure is specified in subclause 5.1 of 3GPP TS 23.380 [36]. The Proxy Mobile IPv6 LMA Initiated Update Notification procedure specified in subclause 5.11 is used to inform the SGW at P-CSCF failure.

This procedure is also used from the PGW to the TWAN or ePDG to provide the UE with a list of available P-CSCF addresses as part of the P-CSCF restoration extension procedure for TWAN access and untrusted WLAN access (3GPP TS 23.380 [36]).

14.2.2 PDN GW procedures

The PDN GW shall follow the update PDP context/Bearer at P-CSCF failure procedure as specified in subclause 5.1 of 3GPP TS 23.380 [36], or the P-CSCF restoration extension procedure for TWAN access and untrusted WLAN access as specified in 3GPP TS 23.380 [36]. When sending the Update Notification message, the PDN GW shall follow the LMA procedure specified in subclause 5.11 as follows:

1. The notification reason shall be set to "PGW-TRIGGERED-PCSCF-RESTORATION-PCO".

2. The Service Selection Mobility Option shall be set to the corresponding APN to which the UE PDN connection is attached

3. The PDN connection ID Mobility Option shall contain the PDN connection ID stored in the BCE if multiple PDN connection to a given APN is supported.

4. The PCO Mobility Option (for S5/S8 and S2a) or the APCO Mobility Option (for S2b) shall contain a list of available P-CSCF addresses.

14.2.3 Serving GW, TWAN and ePDG procedures

The Serving GW shall follow the update PDP context/Bearer at P-CSCF failure procedure as specified in subclause 5.1 of 3GPP TS 23.380 [36]. When receiving the Update Notification message with notification reason "PGW triggered P-CSCF restoration using PCO", the Serving GW shall respond with an Update Notification Acknowledgement message specified as the MAG procedure in subclause 5.11.

The TWAN and ePDG shall follow the P-CSCF restoration extension procedure for TWAN access and untrusted WLAN access as specified in 3GPP TS 23.380 [36]. When receiving the Update Notification message with notification reason "PGW triggered P-CSCF restoration using PCO", the TWAN or ePDG shall respond with an Update Notification Acknowledgement message specified as the MAG procedure in subclause 5.11.

14.3 Inform UE about P-CSCF failure

14.3.1 General

The Inform UE about P-CSCF failure procedure is specified in subclause 5.2 of 3GPP TS 23.380 [36]. The Proxy Mobile IPv6 LMA Initiated Update Notification procedure specified in subclause 5.11 is used to inform the SGW at P-CSCF failure.

14.3.2 PDN GW procedures

The PDN GW shall follow the inform UE about P-CSCF failure procedure as specified in subclause 5.2 of 3GPP TS 23.380 [36]. When sending the Update Notification message, the PDN GW shall follow the LMA procedure specified in subclause 5.11 as follows:

1. The notification reason shall be set to "PGW-TRIGGERED-PCSCF-RESTORATION-DHCP".

2. The Service Selection Mobility Option shall be set to the corresponding APN to which the UE PDN connection is attached

3. The PDN connection ID Mobility Option shall contain the PDN connection ID stored in the BCE if multiple PDN connection to a given APN is supported.

4. The PCO Mobility Option shall contain an indicator that there is P-CSCF failure.

14.3.3 Serving GW procedures

The Serving GW shall follow the inform UE about P-CSCF failure procedure as specified in subclause 5.2 of 3GPP TS 23.380 [36]. When receiving the Update Notification message with notification reason "PGW triggered P-CSCF restoration using DHCP", the Serving GW shall response with an Update Notification Acknowledgement message specified as the MAG procedure in subclause 5.11.