Cisco Cisco Packet Data Gateway (PDG)
MME Changes in Release 17
▀ MME Enhancements for 17.0
▄ Release Change Reference, StarOS Release 17
296
If a specific EMM request is received when the MME is experiencing congestion, the MME will reject/drop
requests for those which include LAPI indicator.
requests for those which include LAPI indicator.
The MME decodes and stores in the UE context/default EPS bearer context, the presence of LAPI indication
from device properties IE if this indicator is set to “MS is configured for NAS signaling low priority” in any of
attach/extended service/TAU/bearer resource allocation/bearer resource modification/PDN connectivity
requests. This is displayed in the output of
from device properties IE if this indicator is set to “MS is configured for NAS signaling low priority” in any of
attach/extended service/TAU/bearer resource allocation/bearer resource modification/PDN connectivity
requests. This is displayed in the output of
show mme session full
command. If the NAS signaling low
priority indication is provided in a PDN CONNECTIVITY REQUEST message, the MME stores the NAS
signaling low priority indication within the PDN context activated due to the PDN connectivity request
procedure.
signaling low priority indication within the PDN context activated due to the PDN connectivity request
procedure.
Congestion Control for Specific APNs:The current CLI configuration for congestion action profile has been
enhanced to take action (reject or drop) during congestion based on APN. Specific APNs can be configured
under the Operator Policy configuration mode to be considered for APN-based congestion control. If a specific
EMM request is received when the MME is experiencing congestion, the MME will reject/drop requests for
those specific APNs.
under the Operator Policy configuration mode to be considered for APN-based congestion control. If a specific
EMM request is received when the MME is experiencing congestion, the MME will reject/drop requests for
those specific APNs.
The existing APN configuration under Operator Policy has been enhanced to define specific APNs for
congestion control.
congestion control.
EMM and/or ESM requests coming from UEs with LAPI indication and/or which match the APNs configured under
the Operator Policy for congestion control will be dropped/rejected if the corresponding request is configured to be
dropped/rejected in congestion-action-profile.
the Operator Policy for congestion control will be dropped/rejected if the corresponding request is configured to be
dropped/rejected in congestion-action-profile.
The Session manager uses the congestion level received from MME manager as part of new requests and uses it for
selection of the appropriate congestion-action-profile (critical/major/minor).
selection of the appropriate congestion-action-profile (critical/major/minor).
The MME has also been enhanced to allow mapping of specific diameter result codes to NAS cause code #42 (Severe
Network Failure). Refer to the
Network Failure). Refer to the
diameter-result-code-mapping s6a
command in the following section for more
information.
Refer also to CSCum37475 - MTC Support : Reject causes with MM & SM back-off time in this document for more
information about related EMM and ESM back-off timers related to congestion control.
information about related EMM and ESM back-off timers related to congestion control.
Command Changes
drop
This command has been enhanced to drop incoming packets based on LAPI (Low Access Priority Indication) or based
on APN when a congestion control threshold has been reached. This functionality is configured using the new
on APN when a congestion control threshold has been reached. This functionality is configured using the new
lapi
and
apn-based
keywords.
Additionally, a new keyword,
brr-ctxt-mod-requests
, has been added to configure the MME to drop Bearer
Context Modification Requests during a congestion condition.
configure
lte-policy
congestion-action-profile profile_name
drop { addn-brr-requests | addn-pdn-connects | brr-ctxt-mod-requests | combined-
attaches | handovers | ps-attaches | s1-setups | service-request | tau-request } [ lapi ]
[ apn-based ]
attaches | handovers | ps-attaches | s1-setups | service-request | tau-request } [ lapi ]
[ apn-based ]
end