G.3 Causes related to PLMN specific network failures and congestion/Authentication Failures
24.0083GPPCore network protocolsMobile radio interface Layer 3 specificationRelease 18Stage 3TS
Cause value = 20 MAC failure
This cause is sent to the network if the USIM detects that the MAC in the AUTHENTICATION REQUEST or AUTHENTICATION_AND_CIPHERING REQUEST message is not fresh (see 3GPP TS 33.102 [5a]).
Cause value = 21 Synch failure
This cause is sent to the network if the USIM detects that the SQN in the AUTHENTICATION REQUEST or AUTHENTICATION_AND_CIPHERING REQUEST message is out of range (see 3GPP TS 33.102 [5a]).
Cause value = 17 Network failure
This cause is sent to the MS if the MSC cannot service an MS generated request because of PLMN failures, e.g. problems in MAP.
Cause value = 22 Congestion
This cause is sent to the MS if the network cannot serve a request from the MS because of congestion (e.g. congestion of the MSC or SGSN or GGSN or PDN Gateway; no channel; facility busy/congested etc.).
Cause value = 23 GSM authentication unacceptable
This cause is sent to the network in Iu mode if a USIM is inserted in the MS and there is no Authentication Parameter AUTN IE present in the AUTHENTICATION REQUEST or AUTHENTICATION_AND_CIPHERING REQUEST message.