Error Handling on SBI Interface

AMF supports the failure handling for SBI interfaces to continue or to terminate the call. This failure handling is supported as per the actions defined under each service, message-type, and status code.

NRF library provides the failure handling template for each NF to handle statistical and dynamical endpoint information. This library integrates with the REST endpoint to handle SBI message requests or responses.

AMF performs failure handling in the following scenarios:

  • When the remote SBI endpoint responds with HTTP error code, it performs the retry procedure as per the failure handling template configuration.

  • When the remote SBI endpoint does not respond within the timeout value, it considers it as an error and proceeds with failure handing.

  • When failure is detected, the REST endpoint checks for retry count in the Failure Handing profile and performs retries.

  • When retries are exhausted or retries aren’t configured, it performs the failure action as configured.

Retransmit happens to the same configured URI.

You can configure response timeout under Failure Handling profile. The default timeout value is 2000 ms.

When multiple status codes are received, the number of retries defined for the first received status code is considered.

For terminate process, the UE context is cleared without any peer communication.

Note
  • AMF supports the primary, secondary, and tertiary IP addresses that are defined in NF-client profile. If the primary address returns an error or times out, try the secondary address. If the secondary address returns an error or times out, try the tertiary address.

  • Retry-and-ignore is supported only for the SMSF interface.

The peer NFs send cause codes to the AMF for each SBI interface. The AMF handles these cause codes received from any SBI interface in each response message as per UE context.

SBI Supported Failure Actions

Parameter

Failure Action

continue

  • Continues the session

  • Rejects the call

terminate

  • Terminates the session

  • Rejects the call

retry-and-terminate

Perform retry as configured

  • If retries are not exhausted, continues the session and the call.

  • If retries are exhausted, terminates the session and rejects the call.

retry-and-continue

Perform retry as configured

  • If retries are not exhausted, continues the session and the call.

  • If retries are exhausted, terminates the session and rejects the call.

retry-and-ignore

Perform retry as configured

  • If retry is passed, continues the session, and continues the call.

  • If retries are exhausted, continues the session, and continues the call (provided no dependency).

SBI Supported Interfaces and Messages

Feature History Table

Feature Name

Release Information

Description

New Failure Handling Messages

2023.03

AMF supports the following new message types as part of the failure handling template configuration.

  • UdmSdmGetUeAmSubscriptionData

  • AmfCommReleaseUeContext

SBI Supported Interfaces and Messages

Interface

Messages

AMF

Service: namf-comm

  • AmfCommUeContextTransfer

  • AmfCommUeContextTransferUpdate

  • AmfCommCreateUeContext

  • AmfCommReleaseUeContext

AUSF

Service: nausf-auth

  • AusfAuthenticationReq

  • AusfAuthenticationCfm

PCF

Service: npcf-am-policy-control

  • PcfAmfPolicyControlCreate

  • PcfAmfPolicyControlDelete

SMF

Service: nsmf-pdusession

  • SmfSmContextCreate

  • SmfSmContextUpdate

  • SmfSmContextDelete

SMSF

Service: nsmsf-sms

  • SmsfActivationReq

  • SmsfDeactivationReq

  • SmsfSendSms

UDM

Service: nudm-sdm

  • UdmSubscriptionReq

  • UdmUnSubscriptionReq

  • UdmSdmGetUeAmSubscriptionData

Service: nudm-uecm

  • UdmRegistrationReq

  • UdmDeRegistrationReq