School of Specs 24.501v20.0.0

3GPP 24.501 v20.0.0 — the document's own text

7.3.2 PDU Session identity

Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The following network procedures shall apply for handling an unknown, erroneous, or unforeseen PDU session identity received in the header of a 5GSM message (specified as the header of a standard L3 message, see 3GPP TS 24.007 [11]) or in the DL NAS TRANSPORT message (see clause 5.4.5) as identified by 5GSM:

  • If the network receives a PDU SESSION MODIFICATION REQUEST message which includes an unassigned or reserved PDU session identity value, the network shall respond with a PDU SESSION MODIFICATION REJECT message including 5GSM cause #43 "invalid PDU session identity".
  • If the network receives PDU SESSION RELEASE REQUEST message which includes an unassigned or reserved PDU session identity value, the network shall respond with a PDU SESSION RELEASE REJECT message including 5GSM cause #43 "invalid PDU session identity".
  • Upon receipt of an UL NAS TRANSPORT message, the network takes the following actions:
    • If the Request type IE is set to "initial request" or "initial emergency request" and the message includes a reserved PDU session identity value, the network shall respond with a DL NAS TRANSPORT message with 5GMM cause #90 "payload was not forwarded";
    • otherwise, if the message includes an unassigned PDU session identity value, a reserved PDU session identity value or an assigned PDU session identity value that does not match an existing PDU session, the network shall respond with a DL NAS TRANSPORT message with 5GMM cause #90 "payload was not forwarded".
  • If the network receives a 5GSM message other than those listed in items a) through c) above in which the message includes a reserved PDU session identity value or an assigned value that does not match an existing PDU session, the network shall ignore the message.

The following UE procedures shall apply for handling an unknown, erroneous, or unforeseen PDU session identity received in the header of a 5GSM message or in the DL NAS TRANSPORT message (see clause 5.4.5) as identified by 5GSM:

  • If the UE receives a 5GSM message which includes an unassigned or reserved PDU session identity value, the UE shall ignore the message.
  • If the UE receives a 5GSM message or DL NAS TRANSPORT message which includes a PDU session identity belonging to any PDU session in state PDU SESSION INACTIVE in the UE, the UE shall respond with a 5GSM STATUS message including 5GSM cause #43 "invalid PDU session identity" and set the PDU session ID in the UL NAS TRANSPORT message to the received PDU session ID as specified in clause 5.4.5.2.