Cisco Cisco Packet Data Gateway (PDG)
MME Changes in Release 17
MME Enhancements for 17.4 ▀
Release Change Reference, StarOS Release 17 ▄
261
CSCuu85658 - Support serving node and handover event for emergency call in
LCS
Feature Changes
Emergency Call Support for Handovers
EMERGENCY_CALL_RELEASE support was described earlier (see CSCus24510). With this, the MME has been
sending EMERGENCY_CALL_RELEASE to the GMLC whenever an emergency call is released, including for
handovers.
sending EMERGENCY_CALL_RELEASE to the GMLC whenever an emergency call is released, including for
handovers.
With support for EMERGENCY_CALL_ HANDOVER event, the MME's LCS functionality is further enhanced to
ensure location continuity during IMS emergency call (PS to CS) handovers.
ensure location continuity during IMS emergency call (PS to CS) handovers.
By supporting the EMERGENCY_CALL_ HANDOVER event, the MME can send the Subscriber Location Report
(SLR) to the configured GMLC** when the SRVCC handover procedure completes. The report includes the UE
Identity (UE's MSISDN, IMSI, IMEI), the target service node ID, and the event type as handover.
(SLR) to the configured GMLC** when the SRVCC handover procedure completes. The report includes the UE
Identity (UE's MSISDN, IMSI, IMEI), the target service node ID, and the event type as handover.
Because MSC ID (expected target serving node ID) is not known to the MME, CLI has been added (see Command
Changes) to map the serving MSC ID to the serving MSC IP-address information (already part of the MME Service
configuration) to derive the needed ISDN number. This configuration is required to enable sending the target serving
node ID for SRVCC handover to the GMLC. This ensures that the GMLC does not receive
EMERGENCY_CALL_RELEASE for a handover event and that the GMLC is aware that the subscriber has moved
from the source MME for location continuity.
Changes) to map the serving MSC ID to the serving MSC IP-address information (already part of the MME Service
configuration) to derive the needed ISDN number. This configuration is required to enable sending the target serving
node ID for SRVCC handover to the GMLC. This ensures that the GMLC does not receive
EMERGENCY_CALL_RELEASE for a handover event and that the GMLC is aware that the subscriber has moved
from the source MME for location continuity.
The MME also includes the MSC identity in the target service node IE (per TS 29.172) as part of the Provide Subscriber
Location Response (PSL), if an MT-LR procedure was in progress during SRVCC handover of an emergency call.
Location Response (PSL), if an MT-LR procedure was in progress during SRVCC handover of an emergency call.
**The MME does not bind all the call events for an emergency call to a specific GMLC peer. As a result, if multiple
GMLC peers are configured, the call events for a single emergency call can be sent to any of the configured GMLC
peers.
GMLC peers are configured, the call events for a single emergency call can be sent to any of the configured GMLC
peers.
For details about configuring MME’s use and configuration of Location Services, refer to the Location Services feature
chapter in the MME Administration Guide.
chapter in the MME Administration Guide.
Command Changes
msc-mapping
This new command creates a mapping between the MSC ISDN number and the MSC’s IP-address (either IPv4 or IPv6)
to ensure location continuity for SRVCC handover. This mapping is required to include the MSV ID in the target
service node IE for the Emergency_Call_Handover event.
to ensure location continuity for SRVCC handover. This mapping is required to include the MSV ID in the target
service node IE for the Emergency_Call_Handover event.
configure
context context_name
mme-service service_name
msc-mapping ip-address { IPv4_address | IPv6_address } isdn isdn_number
no msc-mapping ip-address { IPv4_address | IPv6_address }
end