The Maximum Number of Pdu Sessions Which A UE Can Establish in A PLMN is Limited by Whichever is the lowest of: The Maximum Number of Pdu Session Ids Allowed by The Protocol (As Specified in 3GPP TS 24.007 [11] subclause 11.2.3.1b) , the PLMN's maximum number of PDU sessions and the UE's implementation-specific maximum number of PDU sessions. The maximum number of PDU sessions that the UE
can establish in the PLMN is limited by the lowest of the following two: the maximum number of PDU session IDs allowed by the protocol (as specified in section 11.2.3.1b of 3GPP TS 24.007 [11]), the maximum number of PDU sessions for the PLMN and the implementation-specific maximum number of PDU sessions for the UE.
If during a UE-requested PDU session establishment procedure the 5GSM sublayer in the UE receives an indication that the 5GSM message was not forwarded because the PLMN's maximum number of PDU sessions has been reached, then the UE determines the PLMN's maximum um number of PDU sessions as the number of active PDU sessions it has.
If during the UE-requested PDU session establishment procedure, the 5GSM sublayer in the UE receives an indication that the 5GSM message is not forwarded because the maximum number of PDU sessions for the PLMN has been reached, the UE assigns the PLMN Max The number of PDU sessions is determined as the number of active PDU sessions it has.
NOTE 1: In some situations, when attempting to establish multiple PDU sessions, the number of active PDU sessions that the UE has when 5GMM cause #65 is received is not equal to the maximum number of PDU sessions reached in the network. Note 1
: In some cases, when trying to establish multiple PDU sessions, the UE has a number of active PDU sessions not equal to the maximum number of PDU sessions reached in the network when 5GMM cause#65 is received.
NOTE 2: When the network supports emergency services, it is not expected that 5GMM cause #65 is returned by the network when the UE requests an emergency PDU session. Note 2: When the network supports emergency services, when the UE requests an emergency PDU
session , the network is not expected to return 5GMM reason #65.
NOTE 3: There is only one maximum number of PDU sessions for a PLMN regardless of which access the PDU session exists in
.
NOTE 4: An MA PDU session which (only) has a PDN connection established as a user-plane resource is counted as an active PDU session when determining the PLMN's maximum number of PDU sessions
. , (only) MA PDU sessions with PDN connections established as user plane resources are considered active PDU sessions.
The PLMN's maximum number of PDU sessions applies to the PLMN in which the 5GMM cause #65 "maximum number of PDU sessions reached" is received. When the UE is switched off, when the USIM is removed, or the entry in the "list of subscriber data" for the current SNPN is updated, the UE shall clear all previous determinations representing PLMN's maximum number of PDU sessions. Upon successful registration with a new PLMN, the UE may clear previous determinations representing any PLMN's maximum number(s) of PDU sessions .
The maximum number of PDU sessions for PLMNs applies to PLMNs that receive 5GMM reason #65 "Maximum number of PDU sessions reached". When the UE is switched off, the USIM is removed or the entry in the "Subscriber Data List" of the current SNPN is updated, the UE shall clear all previous determinations representing the maximum number of PDU sessions for the PLMN. After successful registration with the new PLMN, the UE may clear the previous determination indicating the maximum number of PDU sessions for any PLMN.
If the maximum number of established PDU sessions is reached at the UE and the upper layers of the UE request connectivity to a DNN the UE shall not send a PDU SESSION ESTABLISHMENT REQUEST message unless an established PDU session is released. UE needs to release an established PDU session, choosing which PDU session to release is implementation specific, however the UE shall not release the emergency PDU session
. A PDU Session Establishment Request message shall be sent unless an established PDU Session is released. If the UE needs to release an established PDU session, the choice of which PDU session to release is implementation specific, but the UE shall not release an emergency PDU session.
If the UE needs to release a PDU session in order to request an emergency PDU session, it shall either perform a local release of a PDU session or release a PDU session via explicit signaling. If the UE performs a local release, the UE shall:
If the UE needs to release the PDU session to request an emergency PDU session, it shall perform a local release of the PDU session or release the PDU session through explicit signaling. If the UE performs local release, the UE shall:
a) if the PDU session is an MA PDU session:
a) if the PDU session is an MA PDU session:
1) perform a registration procedure for mobility and periodic registration update to indicate PDU session status to the network over each access that user plane resources have been established; and
1) perform registration procedures for mobility and periodic registration updates to indicate to the network the PDU session status on each access that user plane resources have been established; and
2) perform a normal and periodic tracking area updating to indicate EPS bearer context status to the network as specified in clause 5.5.3.2.2 of 3GPP TS 24.301 [15] when a PDN connection has been established as a user plance resource; or
2 ) as described in Section 5.5.3.2.2 of 3GPP TS 24.301 [15], perform normal and periodic tracking area updates to indicate the EPS bearer context status to the network; or b)
if the PDU session is a single access PDU session, perform a registration procedure for mobility and periodic registration update to indicate PDU session status to the network over the access the PDU session is associated with. b
) If the PDU session is a single access PDU session, perform registration for mobility and periodic registration update Procedure to indicate the PDU session status to the network through the access associated with the PDU session.