Update Bearer Procedure Failure Handling
This section covers the PGW-initiated update bearer procedure failure scenarios.
The following table summarizes cnSGW-C behavior during different stages in call processing for various failure types:
Scenarios |
S5/Sx Signaling |
Output |
---|---|---|
Update Bearer Request advance validation failure |
Negative - Update Bearer Response |
No change in Bearer/PDN context. |
Update Bearer Request with non-existing EBIs |
Update Bearer Response with message level cause as REQ_PARTIALLY_ACCEPTED. Bearer level cause for non-existing EBIs as Context Not Found. (Normal handling for existing EBIs) |
Update Bearer Response with message level cause as REQ_PARTIALLY_ACCEPTED. Bearer level cause for non-existing EBIs as CONTEXT_NOT_FOUND. Normal handling for existing EBIs. CDL is updated for existing EBIs only. |
Update Bearer Request is sent to MME and waiting for the response |
Negative - Update Bearer Response |
Negative - Update Bearer Response CDL is not updated. |
S11 Update Bearer Response (Message level Cause == CONTEXT_NOT_FOUND) and S5 Update Bearer Req/Rsp had default bearer in the bearer context list |
Sx Delete Req/Rsp Negative - Update Bearer Response |
Negative - Update Bearer Response CDL is not updated. Statistics/Transactional Logs PDN Key Release + PDN deallocation If this is the last PDN, then resource manager is released, all subscriber keys are released and subscriber deallocation is done. |
S11 Update Bearer Response (Message level Cause == CONTEXT_NOT_FOUND) and S5 Update Bearer Req/Rsp didn't have default bearer in the bearer context list |
Sx Modify Req/Rsp Negative - Update Bearer Response |
CDL is not updated. |
S11 Update Bearer Response (Message level Cause == REQ_PARTIALLY_ACCEPTED, Bearer Context Cause == Any failure for dedicated bearer) |
Sx Modify Req/Rsp Update Bearer Response with message level cause as REQ_PARTIALLY_ACCEPTED |
Update Bearer Response with message level cause as REQ_PARTIALLY_ACCEPTED CDL is updated for successful bearers. |
S11 Update Bearer Response (Message level Cause == REQ_PARTIALLY_ACCEPTED, Bearer Context Cause == CONTEXT_NOT_FOUND for default bearer) |
Sx Delete Req/Rsp Negative - Update Bearer Response |
Negative - Update Bearer Response CDL is not updated. PDN Key Release and PDN deallocation If this is the last PDN, then resource manager is released, all subscriber keys are released and subscriber deallocation is done. |
If Sx modify is triggered after Update Bearer Response:
|
Ignore failure and continue |
Ignore failure and continue |
If Sx Modify is triggered after Update Bearer Response:
|
||
If Sx Delete is triggered after Update Bearer Response:
|
Ignore failure and continue |
Ignore failure and continue |
-
Sx Failure Cause received as part of Sx Session Modification Response
-
Context Not Found
-
SGW Behavior (New Transaction):
-
SGW triggers S11 Delete Bearer Request and S5 Delete Session Request to delete that PDN
-
No Sx Signaling
SGW Behavior (Update Bearer Transaction): SGW sends S5 Update Bearer Response with Cause as No Resource Available, as part of Update Bearer Procedure Transaction. Also, SGW doesn’t initiate any signaling towards UP as soon as it receives Sx Session Modification Response with cause as Context Not Found.
-
Sx Failure Cause received as part of Sx Session Modification Response
-
Context Not Found
-
SGW Behavior (New Transaction):
-
SGW triggers S11 Delete Bearer Request and S5 Delete Session Request to delete that PDN
-
No Sx Signaling
SGW Behavior (Update Bearer Transaction): SGW sends S5 Update Bearer Response with Cause as No Resource Available, as part of Update Bearer Procedure Transaction. Also, SGW doesn’t initiate any signaling towards UP as soon as it receives Sx Session Modification Response with cause as Context Not Found.