Cisco Cisco Packet Data Gateway (PDG) Nota Di Rilascio
MME Changes in Release 15.0
MME Enhancements for September 30, 2013 ▀
Cisco ASR 5x00 Release Change Reference ▄
329
New Behavior: This enhancement allows for a new configuration that can be used to apply restrictions on new foreign-
plmn-guti. The behavior for Attach and TAU Requests with a foreign GUTI from a local PLMN (either the MME's own
PLMN or a network sharing PLMN) has not been changed.
plmn-guti. The behavior for Attach and TAU Requests with a foreign GUTI from a local PLMN (either the MME's own
PLMN or a network sharing PLMN) has not been changed.
See the
foreign-plmn-guti-mgmt-db
and
plmn
commands in this chapter for configuration information.
Inter-RAT GW Co-location Selection Improvements
In previous releases, node selection on the MME relied on DNS NAPTR procedures for node discovery as defined by
3GPP. Co-location of S-GW and P-GW was only possible when FQDNs are known for both S-GW and P-GW. During
Gn/Gp handoffs, the P-GW is anchored and the S-GW alone needs to be selected. The MME does not learn the P-GW-
FQDN from the old SGSN. As a result, selection of an S-GW co-located with the already anchored PGW is not viable.
3GPP. Co-location of S-GW and P-GW was only possible when FQDNs are known for both S-GW and P-GW. During
Gn/Gp handoffs, the P-GW is anchored and the S-GW alone needs to be selected. The MME does not learn the P-GW-
FQDN from the old SGSN. As a result, selection of an S-GW co-located with the already anchored PGW is not viable.
This feature enhances the MME's node-selection logic to ensure the selection of co-located S-GW with the anchored P-
GW during Gn/Gp handoffs. The MME will construct the APN FQDN based on the APN name received from old-
SGSN. The MME performs DNS queries for both TAI-FQDN (for S-GW) and APN-FQDN (for P-GW) and constructs
a list of node-pairs, sorted in the order of highest degree match, anchors the P-GW-node matching the IP address
received from old-SGSN and then selects the S-GW following the same principles of node-selection. This results in the
selection of a co-located S-GW (if present), or in the selection of a topologically closer S-GW.
GW during Gn/Gp handoffs. The MME will construct the APN FQDN based on the APN name received from old-
SGSN. The MME performs DNS queries for both TAI-FQDN (for S-GW) and APN-FQDN (for P-GW) and constructs
a list of node-pairs, sorted in the order of highest degree match, anchors the P-GW-node matching the IP address
received from old-SGSN and then selects the S-GW following the same principles of node-selection. This results in the
selection of a co-located S-GW (if present), or in the selection of a topologically closer S-GW.
This feature ensures that the load balancing and colocation benefits on the bearer plane are maintained across Inter-RAT
HO scenarios.
HO scenarios.
Refer to the
policy inter-rat
command in the Modified MME Commands section of this document more
information.
Lawful Intercept Enhancements
When Camp-on is configured, the MME now sends an Session Event Active signal to the Lawful Intercept server when
starting an interception for an active subscriber.
starting an interception for an active subscriber.
Location Services
The MME now supports additional Location Services (LCS) functionality:
MT-LR procedures from the GMLC with client type of Lawful Intercept and Emergency services.
Network Induced (NI-LR) procedures for Emergency PDN Connect and Emergency Attach, and Inbound
relocation with emergency PDN (through TAU or SRNS).
Circuit Switch Fallback (CSFB): When a UE is combined attached to the MME, and the CSFB registration is not
for SMS-only services, the MME shall page UE on receipt of an SGs page with LCS Client identity.
Multiple Attach Request Handling
The MME now complies with 3GPP TS 24.301 for Attach Request collisions as follows:
A second attach coming in an INITIAL UE message aborts the ongoing auth/pdn-connect procedures only when
the Attach Request has IE changes.
Mobile-ID is no longer considered in the Attach Req NAS message comparison.
Multiple MMEC Configuration in S1 Setup
Previous Behavior: Each MME in an MME pool is uniquely identified by one MME code (MMEC), which is used to
build the GUTI assigned to the users attaching on that MME. In previous releases, only a single MMEC and MMEGI
could be configured for a given MME service.
build the GUTI assigned to the users attaching on that MME. In previous releases, only a single MMEC and MMEGI
could be configured for a given MME service.