Cisco Cisco Packet Data Interworking Function (PDIF)
MME Changes in Release 17
▀ MME Enhancements for 17.4
▄ Release Change Reference, StarOS Release 17
252
The call release event enables the GMLC to clear the cache for existing calls and to correctly log the duration of an
emergency call. Without call release facilitating the clearing of the cache, the location platform could send the old
(erroneous) location information in response to a new location request for an E-911 call.
emergency call. Without call release facilitating the clearing of the cache, the location platform could send the old
(erroneous) location information in response to a new location request for an E-911 call.
Previous Behavior: The GMLC was not notified when the MME performed an Emergency Call Release as part of a
location service procedure.
location service procedure.
New Behavior: In compliance with 3GPP TS 29.172, the MME LoCation Services (LCS) feature supports sending the
EMERGENCY_CALL_RELEASE event in a subscriber location report (SLR) request message, to the GMLC to notify
the GMLC of the call release, when an emergency call is released or when an emergency PDN is disconnected at the
MME.
EMERGENCY_CALL_RELEASE event in a subscriber location report (SLR) request message, to the GMLC to notify
the GMLC of the call release, when an emergency call is released or when an emergency PDN is disconnected at the
MME.
Note, this is not configurable functionality.
Customer Impact: Notifying the GMLC of the emergency call release event allows the GMLC to delete all information
previously stored for the emergency call in accordance with regulations.
previously stored for the emergency call in accordance with regulations.
CSCus32369, CSCuv66398 - wrong type of list TAI list IE sent in ATTACH/TAU
Accept
Feature Changes
TAI List IE Value Encoding
Previous Behavior: Tracking Area Identity (TAI) list IE, sent in ATTACH/TAU Accept from MME are incorrectly
encoded. As per 3GPP TS 24.301 (clause 9.9.3.33), three different values are possible for encoding the TAI list:
encoded. As per 3GPP TS 24.301 (clause 9.9.3.33), three different values are possible for encoding the TAI list:
“000”, list of TACs belonging to one PLMN, with non-consecutive TAC values
“001”, list of TACs belonging to one PLMN, with consecutive TAC values
“010”, list of TAIs belonging to different PLMNs
The MME sends incorrectly encoded Tracking Area Identity (TAI) list IE in ATTACH/TAU Accept messages.
Irrespective of the TAC (Tracking Area Code) values and the PLMN configuration, the type of list value used is "010".
Based on the 3GPP TS 24.301 options listed above, this encoding is incorrect when consecutive or non-consecutive
TAC values, belonging to the same PLMN, are configured.
Irrespective of the TAC (Tracking Area Code) values and the PLMN configuration, the type of list value used is "010".
Based on the 3GPP TS 24.301 options listed above, this encoding is incorrect when consecutive or non-consecutive
TAC values, belonging to the same PLMN, are configured.
New Behavior: The MME now encodes the TAI list IE value per the 3GPP TS 24.301 so that the MME automatically
encodes "000", "001", or “010” depending upon the TAC values and PLMN configuration.
encodes "000", "001", or “010” depending upon the TAC values and PLMN configuration.
This change is applicable for releases 17.4 and forward. A new CLI (PR CSCuv66398) ensures backward compatibility
with previous releases, as it disables this behavior change (PRCSCus32369). This new CLI command,
with previous releases, as it disables this behavior change (PRCSCus32369). This new CLI command,
legacy-tai-
list-encoding
, is introduced under the MME Service configuration mode to configure the encoding for the TAI list
value as "010" for list of TAIs belonging to different PLMNs.
Command Changes
legacy-tai-list-encoding
This new command is added to enable the MME to override the new default behavior and to specify the "010" encoding
value for the TAI (Tracking Area Identity) list IE. If this command is not used for the configuration, then the MME uses
the default function to encode the TAI list value for the IE based on the list of Tics belonging to one PLMN, with
consecutive or non-consecutive TAC values configured in the TAI entries.
value for the TAI (Tracking Area Identity) list IE. If this command is not used for the configuration, then the MME uses
the default function to encode the TAI list value for the IE based on the list of Tics belonging to one PLMN, with
consecutive or non-consecutive TAC values configured in the TAI entries.