22 Downlink Data Notification Handling at MME/S4 SGSN

23.0073GPPRelease 18Restoration proceduresTS

If the MME/S4 SGSN receives a Downlink Data Notification message from the SGW as a result of the SGW having received an Error Indication message from the eNodeB/RNC or S4-SGSN over S4 User Plane, the MME/S4 SGSN should perform the following:

– If the UE is in IDLE state, upon receipt of the Downlink Data Notification message, the MME/S4 SGSN shall perform the Network Triggered Service Request procedure as specified in 3GPP TS 23.060 [5] and 3GPP TS 23.401 [15].

– If the UE is in CONNECTED state, upon receipt of the Downlink Data Notification message, the MME shall perform S1 Release procedure and perform Network Triggered Service Request procedure as specified in 3GPP TS 23.401 [15].

– If the UE is in CONNECTED state, upon receipt of the Downlink Data Notification message and Direct Tunnel is used, the S4-SGSN shall perform Iu Release procedure and perform Network Triggered Service Request procedure as specified in 3GPP TS 23.060 [5] if the cause value included in Downlink Data Notification is "Error Indication received from RNC/eNodeB/S4-SGSN",

– If the UE is in CONNECTED state, upon receipt of the Downlink Data Notification message and Direct Tunnel is not used, the S4-SGSN should re-establish all of the S4-U bearers of this UE if the cause value included in Downlink Data Notification is "Error Indication received from RNC/eNodeB/S4-SGSN".

Upon receipt of a Downlink Data Notification message from the SGW, caused by an Error Indication message received from the MME over the S11 User Plane, the MME should perform the following if the UE is known by the MME:

– If the UE is in IDLE state, the MME shall perform the Network Triggered Service Request procedure as specified in 3GPP TS 23.401 [15].

– If the UE is in CONNECTED state, the MME may perform an S1 Release procedure and a Network Triggered Service Request procedure as specified in 3GPP TS 23.401 [15], or as an alternative, the MME may keep the existing S1 signalling connection and just send a Modify Bearer Request message to the SGW to re-establish the S11-U tunnel.

If the MME receives a Downlink Data Notification message from the SGW as a result of the SGW having detected a S1-U path failure, and if the MME supports S1-U path failure notification feature, the MME shall behave as specified in clause 20.3.6.