S-GW Paging includes the following scenarios:
Scenario 1: S-GW sends a DDN message to the MME/S4-SGSN nodes. MME/S4-SGSN responds to the S-GW with a DDN Ack message. While waiting for the DDN Ack message from the MME/S4-SGSN, if the S-GW receives a high priority downlink data, it does not resend a DDN to the MME/S4-SGSN.
Scenario 2: If a DDN is sent to an MME/S4-SGSN and TAU/RAU MBR is received from another MME/S4-SGSN, S-GW does not send DDN.
Scenario 3: DDN is sent to an MME/S4-SGSN and DDN Ack with Cause #110 is received. DDN Ack with cause 110 is treated as DDN failure and standard DDN failure action procedure is initiated.
High Priority DDN at S-GW
MBR-DDN Collision Handling
Higher priority DDN on S-GW and SAEGW, which helps MME/S4-SGSN to prioritize paging.
Enhanced paging KPI and VoLTE services.
DDN message and mobility procedure so that DDN is not lost.
MBR guard timer, which is started when DDN Ack with temporary HO is received. A new CLI command ddn temp-ho-rejection mbr-guard-timer has been introduced to enable the guard timer to wait for MBR once the DDN Ack with cause #110 (Temporary Handover In Progress) is received.
TAU/RAU with control node change triggered DDNs.
In addition to the above functionality, to be compliant with 3GPP standards, support has been enhanced for Downlink Data Notification message and Mobility procedures. As a result, DDN message and downlink data which triggers DDN is not lost. This helps improve paging KPI and VoLTE success rates in scenarios where DDN is initiated because of SIP invite data.
This is a license-controlled feature. Contact your Cisco account or support representative for detailed licensing information.