Cisco Cisco Packet Data Gateway (PDG)
MME Changes in Release 16
▀ MME Enhancements for 16.4
▄ Release Change Reference, StarOS Release 16
214
Performance Indicator Changes
tai Schema
Missing stat added to the tai schema for pegging and display.
tai-emm-msgtx-csg-not-subscribed
CSCuq57243 - MME does E-RAB release at the end of CS HO
Feature Changes
MME Sends UE Context Release after CS HO
Modifications in this release impact the handling of MME call flows to the UE/eNodeb-side after an SRVCC (Single
Radio Voice Call Continuity) procedure completes in a scenario where calls are handed between VoLTE and legacy
Circuit Switched systems for CS-only handover.
Radio Voice Call Continuity) procedure completes in a scenario where calls are handed between VoLTE and legacy
Circuit Switched systems for CS-only handover.
Previous Behavior: During the bearer deletion process, the MME used to send an E-RAB Release to the eNodeB at the
end of the SRVCC procedure. Typically, the eNodeB responded to the MME’s E-RAB Release with a NAS Non-
Delivery message because the UE moved to another RAT due to handover.
end of the SRVCC procedure. Typically, the eNodeB responded to the MME’s E-RAB Release with a NAS Non-
Delivery message because the UE moved to another RAT due to handover.
New Behavior: Now at the end of the CS-only handover SRVCC procedure, the MME sends a UE Context Release, in
place of an E-RAB Release, with the cause 'Successful-handover'. This ensures the eNodeB can properly respond to the
Release message and behave appropriately at both the radio-side and the UE-side
place of an E-RAB Release, with the cause 'Successful-handover'. This ensures the eNodeB can properly respond to the
Release message and behave appropriately at both the radio-side and the UE-side
Customer Impact: Reduces signaling to the eNodeB.
CSCuq88194 - New Reject cause needs to be added under Bearer Alloc Reject
ESM message
Feature Changes
Counter and Stats Added to Track Reject Cause
Previous Behavior: The “EPS QoS Not Accepted” reject cause was not available for use in Bearer Alloc Reject ESM
control messages.
control messages.
New Behavior: The “EPS QoS Not Accepted” reject cause code is now supported for use in the Bearer Alloc Reject
ESM control message. This cause code is received when UE-initiated dedicated bearer request is rejected by the MME
as a result of the MME’s configuration settings in the APN Profile - ‘reject’ option set with the
ESM control message. This cause code is received when UE-initiated dedicated bearer request is rejected by the MME
as a result of the MME’s configuration settings in the APN Profile - ‘reject’ option set with the
dedicated-bearers
{ gbr | non-gbr }
command.
Corresponding counter and bulk statistic variable have been added to track the use of this cause code.
Customer Impact: Support for this cause code will assist customers to debug the reject cause for bearer allocation
failures.
failures.