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Cisco Bug: CSCvu65256 - MME is sending cause misc: Unspecified for e-RAB ID 7 in PathSwitch Req Ack message during X2 HO

Last Modified

Sep 17, 2020

Products (2)

  • Cisco ASR 5000 Series
  • Cisco ASR 5500

Known Affected Releases

21.17.6 21.17.8

Description (partial)

Symptom:
During X2 handover procedure, MME is replying to Target eNodeB with misc: Unspecified for e-RAB ID 7 inside IE id-E-RABToBeReleasesList in PathSwitch Req Ack message

Scenario:
========
1. Basic Attach Complete with default PDN (EBI - 5) 2. Additional PDN established (EBI - 6) 3. Network initiated default bearer deletion (EBI - 6) with cause normal release.
4. E-RAB Release with bearer id 6 in failed list due to X2 handover triggered.
5. X2-HO Path switch request
6. DBR response
7. Path switch request acknowledge

In step 4, since X2 handover is triggered in source eNB, bearer id 6 is not released and hence it is sent in failed list in E-RAB Release response message. 
In step 7, this bearer id 6 is added in E-RAB to be released list in Path Switch Request Ack message with cause miscellaneous and cause value as unspecified instead of NAS cause and value as normal release. Hence KPI is degraded.

Conditions:
X2 HO
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