Section: .1 Delete Session Request
Content: The direction of this message shall be from MME/S4-SGSN to SGW, from SGW to PGW and from TWAN/ePDG to PGW (see Table 6.1-1). A Delete Session Request message shall be sent on the S11 interface by the MME to the SGW and on the S5/S8 interface by the SGW to the PGW for a UE having at least one PDN connection through the SGW and PGW, as part of the procedures: - EUTRAN Initial Attach - UE, HSS or MME Initiated Detach - UE or MME Requested PDN Disconnection It shall also be sent on the S4 interface by the SGSN to the SGW, and on the S5/S8 interface by the SGW to the PGW as part of - MS, HLR or SGSN initiated detach procedure - Combined GPRS/IMSI Attach - MS and SGSN Initiated PDN connection Deactivation Procedure using S4 On the S11 interface by the MME to the SGW as part of the procedures: - Tracking Area Update with SGW Change - S1 Based Handover with SGW Change - X2 Based Handover with SGW Relocation - E-UTRAN to UTRAN Iu mode Inter RAT handover with SGW change - E-UTRAN to GERAN A/Gb mode Inter RAT handover with SGW change - Inter RAT handover cancel with SGW change - MME to Gn/Gp SGSN combined hard handover and SRNS relocation procedure - MME to SGSN Routing Area Update - E-UTRAN to Gn/Gp SGSN Inter RAT handover - S1 Based handover cancel with SGW change - Optimised Active Handover: E-UTRAN Access to CDMA2000 HRPD Access - MME triggered Serving GW relocation And on the S4 interface by the SGSN to the SGW as part of - Enhanced Serving RNS Relocation with SGW relocation using S4 - Routing Area Update with SGW change - SGSN to MME Tracking Area Update with SGW change - SRNS Relocation Cancel Procedure Using S4 - Inter RAT with SGW change handover cancel - Serving RNS relocation with SGW change - UTRAN Iu mode to E-UTRAN Inter RAT handover with SGW change - GERAN A/Gb mode to E-UTRAN Inter RAT handover with SGW change - S4 SGSN to Gn/Gp SGSN Routeing Area Update - S4 SGSN to Gn/Gp SGSN Serving RNS Relocation Procedures - S4 SGSN to Gn/Gp SGSN PS handover Procedures - S4-SGSN triggered Serving GW relocation The message shall also be sent on the S2b interface by the ePDG to the PGW as part of procedures: - UE/ePDG Initiated Detach with GTP on S2b - UE Requested PDN Disconnection with GTP on S2b - HSS/AAA Initiated Detach with GTP on S2b The message shall also be sent on the S2a interface by the TWAN to the PGW as part of procedures: - UE/TWAN Initiated Detach and UE/TWAN Requested PDN Disconnection in WLAN on GTP S2a - HSS/AAA Initiated Detach in WLAN on GTP S2a This message may also be sent on S5/S8 interface by the SGW to the PGW: - If Downlink Data Notification Acknowledge message with Context not found cause value is received. During the detach procedure, if ISR is active and SGW receives a Delete Session Request, the SGW shall deactivate the ISR. NOTE: The SGW can determine if it is a detach procedure based on e.g. it receives a Delete Session Request message for the last PDN Connection. When ISR is active, during the Detach procedure the SGW shall forward the Delete Session Request message to the PGW on the S5/S8 interface after receiving both of the messages sent from the MME and the SGSN for the same PDN Connection. If there are any procedure collisions, the Delete Session Request shall have precedence over any other Tunnel Management message. During the handover procedure the Delete Session Request message shall not release the indirect data forwarding tunnels. Possible Cause values are: - "ISR deactivation ". - "Network Failure". - "QoS parameter mismatch". Table .1-1 specifies the presence of the IEs in the message. Table 7.2.9.1-1: Information Elements in a Delete Session Request Table 7.2.9.1-2: Overload Control Information within Delete Session Request