Cisco Cisco Packet Data Gateway (PDG)
MME Changes in Release 17
▀ MME Enhancements for 17.2
▄ Release Change Reference, StarOS Release 17
278
CSCus18004 - MME rounds down max bitrate in VoLTE leading to packet loss
Feature Changes
Rounding Up Some Assigned QoS Values
MME rounded down the MBR and GBR values for both Uplink and Downlink in some scenarios. This behavior has
been modified to support rounding up in place of rounding down - as described below.
been modified to support rounding up in place of rounding down - as described below.
Previous Behavior: MME rounded down the assigned QoS values if the requested QoS did not align in order of 8
(<576Kbit/s) or 64 (<8640Kbit/s) and in order of 100kbps(<16000Kbit/s), (<=128000Kbit/s)1Mbps and
(<256000Kbit/s) 2Mbps increments for extended values. For example, if the requested QoS value is 78Kbps the MME
rounded down the QoS to 72Kbps.
(<576Kbit/s) or 64 (<8640Kbit/s) and in order of 100kbps(<16000Kbit/s), (<=128000Kbit/s)1Mbps and
(<256000Kbit/s) 2Mbps increments for extended values. For example, if the requested QoS value is 78Kbps the MME
rounded down the QoS to 72Kbps.
New Behavior: MME rounds up the assigned QoS values if the requested QoS is not aligning in order of 8
(<576Kbit/s) or 64 (<8640Kbit/s) and in order of 100kbps(<16000Kbit/s), (<=128000Kbit/s)1Mbps and
(<256000Kbit/s)2Mbps increments for extended values. For example, if the requested QoS value is 78Kbps the MME
rounds up the QoS to 80Kbps.
(<576Kbit/s) or 64 (<8640Kbit/s) and in order of 100kbps(<16000Kbit/s), (<=128000Kbit/s)1Mbps and
(<256000Kbit/s)2Mbps increments for extended values. For example, if the requested QoS value is 78Kbps the MME
rounds up the QoS to 80Kbps.
During 4G to 3G (S3 to S4-SGSN) RAU, the MME does not send rounded QoS value to the SGSN. The SGSN is left to
make the decision to round up or round down.
make the decision to round up or round down.
CSCus36547, CSCur89572 - ’State/Location Information Retrieval’ flag support
in Feature-list AVP
Feature Changes
State/Location Information Retrieval’ Flag
With this release, the MME now sends the “State/Location-Information-Retrieval” flag set in the Feature-List AVP of
the Update Location Request (ULR) message over the S6a interface to the HSS at the time the UE attaches. With the
“State/Location-Information-Retrieval” flag set, the HSS knows to set the “EPS User State Request”, “EPS Location
Information Request” and “Current Location Request” bits in the IDR-Flags AVP in IDR messages towards the MME.
This subscriber data provides the UE’s current location information needed in multiple service scenarios, such as
VoLTE services on the IMS side.
the Update Location Request (ULR) message over the S6a interface to the HSS at the time the UE attaches. With the
“State/Location-Information-Retrieval” flag set, the HSS knows to set the “EPS User State Request”, “EPS Location
Information Request” and “Current Location Request” bits in the IDR-Flags AVP in IDR messages towards the MME.
This subscriber data provides the UE’s current location information needed in multiple service scenarios, such as
VoLTE services on the IMS side.
MME behavior for IDR-initiated Paging: Upon receipt of an IDR message with the “Current Location Request” bit
set in the IDR-Flags AVP, the MME behavior complies with Feature-List AVP, IDR-Flags AVP, and EPS-Location-
Information AVP sections as specified in 3GPP TS 29.272 v11.9.0. So when the IDR messages are received with “EPS
Location Information Request” and “Current Location Request” bits set in IDR-Flags AVP, the MME sends the UE's
current location information or the UE's last known location information in the “EPS-Location-Information” AVP of the
IDA message
set in the IDR-Flags AVP, the MME behavior complies with Feature-List AVP, IDR-Flags AVP, and EPS-Location-
Information AVP sections as specified in 3GPP TS 29.272 v11.9.0. So when the IDR messages are received with “EPS
Location Information Request” and “Current Location Request” bits set in IDR-Flags AVP, the MME sends the UE's
current location information or the UE's last known location information in the “EPS-Location-Information” AVP of the
IDA message
If IDR is received with “EPS Location Information Request” and “Current Location Request” flags set in IDR-Flags
AVP, the the MME's IDA response depends on whether :
AVP, the the MME's IDA response depends on whether :
the UE is in connected mode with Location Reporting active making location information available, then the
MME sends the IDA message without “Current-Location-Retrieved” AVP in “EPS-Location-Information”
AVP.
AVP.
the UE is in connected mode without Location Reporting active so location information is not available, then the
MME sends a Location-Reporting-Control message to the eNB to get the ECGI and the TAI.