Cisco Cisco Packet Data Gateway (PDG) Nota De Lançamento
MME Changes in Release 15.0
▀ MME Enhancements for October 31, 2014
▄ Cisco ASR 5x00 Release Change Reference
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CSCuq28652 - Low S1 signalling and low response for TAU requests
Feature Changes
Improved Handling During High Watermark in IMSIMGR
Previous Behavior: When a Session Manager facility reached the high watermark limit, the IMSI manager facility
begins to drop MME calls.
begins to drop MME calls.
New Behavior: Now when the high watermark limit is reached, subscribers will be moved to different Session
Manager.
Manager.
Customer Impact: Subscribers will no longer be dropped when the high watermark limit is reached on a given Session
Manager.
Manager.
CSCuq51479 - MME-CSFB: Handling of CSFB procedure for ongoing handover
Feature Changes
Behavior Change for CSFB Procedure During Ongoing Handover
Previous Behavior: If a Mobile Terminated (MT) Call received when an InterRAT, S1, or X2 Handover is in progress,
the MME will process the SGS paging.
the MME will process the SGS paging.
New Behavior: If a MT Call is received when an InterRAT Handover is in-progress, the MME will ignore the SGS
paging.
paging.
If a MT call is received during ongoing S1/X2 handover, the MME will delay the procedure start until the handover
completes.
completes.
In the case of a handover failure, the subsequent retransmission of SGS paging will trigger paging towards UE.
CSCuq74468 - MME TAU release cause with ESM failure when PGW is not
reponding
Feature Changes
Separate Local Cause Mapping for Attach and TAU Procedures
Previous Behavior: The default cause-code mapping whenever the error condition “GW not reachable” occurs is set to
ESM-FAILURE for both Attach and TAU procedures. For a TAU procedure, the default cause to be sent should be NO-
EPS-BEARER-CONTEXT-ACTIVATED in the reject message. There is no current capability to configure this cause
code mapping on the MME. Also, there is no option to specify the cause-code mapping separately for Attach and TAU
procedures, which results in assigning the same cause code for both.
ESM-FAILURE for both Attach and TAU procedures. For a TAU procedure, the default cause to be sent should be NO-
EPS-BEARER-CONTEXT-ACTIVATED in the reject message. There is no current capability to configure this cause
code mapping on the MME. Also, there is no option to specify the cause-code mapping separately for Attach and TAU
procedures, which results in assigning the same cause code for both.
New Behavior: The MME can now be configured to return separate cause codes for ATTACH and TAU procedures
whenever the error condition “GW not reachable” occurs.
whenever the error condition “GW not reachable” occurs.