Section: 7.3.1 Procedure transaction identity
Content: The following network procedures shall apply for handling an unknown, erroneous, or unforeseen PTI received in a 5GSM message: a) In case the network receives a PDU SESSION MODIFICATION COMPLETE, a PDU SESSION RELEASE COMPLETE message or a PDU SESSION MODIFICATION COMMAND REJECT message in which the PTI value is an assigned or unassigned value that does not match any PTI in use, the network shall respond with a 5GSM STATUS message including 5GSM cause #47 "PTI mismatch". b) In case the network receives a PDU SESSION AUTHENTICATION COMPLETE message or a SERVICE-LEVEL AUTHENTICATION COMPLETE message in which the PTI value is an assigned value, the network shall respond with a 5GSM STATUS message including 5GSM cause #81 "invalid PTI value". c) In case the network receives a PDU SESSION ESTABLISHMENT REQUEST message, a PDU SESSION MODIFICATION REQUEST message or a PDU SESSION RELEASE REQUEST message in which the PTI value is an unassigned value, the network shall respond with a 5GSM STATUS message including 5GSM cause #81 "invalid PTI value". d) In case the network receives a 5GSM message in which the PTI value is a reserved value, the network shall ignore the message. The following UE procedures shall apply for handling an unknown, erroneous, or unforeseen PTI received in a 5GSM message: a) In case the UE receives a PDU SESSION MODIFICATION COMMAND message or a PDU SESSION MODIFICATION REJECT message in which the PTI value is an assigned value that does not match any PTI in use: 1) if the UE detects that this PDU SESSION MODIFICATION COMMAND message is a network retransmission of an already accepted request (see subclause 6.3.2.3), the UE shall respond with a PDU SESSION MODIFICATION COMPLETE message; 2) if the UE detects that this PDU SESSION MODIFICATION COMMAND message is a network retransmission of an already rejected request (see subclause 6.3.2.4), the UE shall respond with a PDU SESSION MODIFICATION COMAND REJECT message; or 3) otherwise, the UE shall respond with a 5GSM STATUS message including 5GSM cause #47 "PTI mismatch". b) In case the UE receives a PDU SESSION RELEASE COMMAND message or a PDU SESSION RELEASE REJECT message in which the PTI value is an assigned value that does not match any PTI in use: 1) if the UE detects that this PDU SESSION RELEASE COMMAND message is a network retransmission of an already accepted request (see subclause 6.3.3.3), the UE shall respond with a PDU SESSION RELEASE COMPLETE message; or 2) otherwise, the UE shall respond with a 5GSM STATUS message including 5GSM cause #47 "PTI mismatch". c) In case the UE receives a PDU SESSION ESTABLISHMENT ACCEPT message or a PDU SESSION ESTABLISHMENT REJECT message in which the PTI value is an assigned value that does not match any PTI in use: 1) the UE shall respond with a 5GSM STATUS message including 5GSM cause #47 "PTI mismatch". d) In case the UE receives a PDU SESSION AUTHENTICATION COMMAND message, a PDU SESSION AUTHENTICATION RESULT message or a SERVICE-LEVEL AUTHENTICATION COMMAND message in which the PTI value is an assigned value, the UE shall respond with a 5GSM STATUS message including 5GSM cause #81 "invalid PTI value". e) In case the UE receives a PDU SESSION ESTABLISHMENT ACCEPT message, a PDU SESSION ESTABLISHMENT REJECT message, a PDU SESSION MODIFICATION REJECT message or a PDU SESSION RELEASE REJECT message in which the PTI value is an unassigned value, the UE shall ignore the message. f) In case the UE receives a 5GSM message in which the PTI value is a reserved value, the UE shall ignore the message.