5.2.1 Service Description
29.5023GPP5G SystemRelease 16Session Management ServicesStage 3TS
The Nsmf_PDUSession service operates on the PDU Sessions. The service operations exposed by this service allow other NFs to establish, modify and release the PDU Sessions. The following are the key functionalities of this NF service:
– Creation, modification and deletion of SM contexts for PDU Sessions; an SM context represents an association between the NF Service Consumer (e.g. AMF) and the SMF for a PDU session;
– Retrieval of SM contexts of PDU sessions (i.e. UE EPS PDN connection or complete SM context), e.g. to move PDU sessions towards the EPC using the N26 interface or to transfer SM contexts between I-SMFs or V-SMFs over the N38 interface;
– Creation, modification and deletion of PDU sessions between the V-SMF and H-SMF in HR roaming scenarios, or between the I-SMF and SMF for PDU sessions involving an I-SMF;
– Sending of mobile originated data (received over NAS) for a PDU session to the SMF, V-SMF in HR roaming scenarios, or I-SMF for PDU sessions involving an I-SMF;
– Transferring of NEF anchored mobile originated data for a PDU session to the H-SMF in HR roaming scenarios, or SMF for PDU sessions involving an I-SMF;
– Transferring of NEF anchored mobile terminated data for a PDU session to the V-SMF in HR roaming scenarios, or I-SMF for PDU sessions involving an I-SMF;
– Association of policy and charging rules with PDU Sessions and binding the policy and charging rules to flows;
– Interacting with the UPF over N4 for creating, modifying and releasing user plane sessions;
– Process user plane events from the UPF and apply the corresponding policy and charging rules.
The Nsmf_PDUSession service supports the following service operations.
Table 5.2.1-1: Service operations supported by the Nsmf_PDUSession service
|
Service Operations |
Description |
Operation Semantics |
Example Consumer(s) |
|
Create SM Context |
Create an SM context in SMF, or in V-SMF in HR roaming scenarios, or in I-SMF during the I-SMF insertion and change scenarios, for a PDU session. |
Request/Response |
AMF |
|
Update SM Context |
Update the SM context of a PDU session and/or provide the SMF with N1 or N2 SM information received from the UE or from the AN. |
Request/Response |
AMF, I-SMF |
|
Release SM Context |
Release the SM context of a PDU session when the PDU session has been released. |
Request/Response |
AMF |
|
Notify SM Context Status (NOTE 1) |
Notify the NF Service Consumer about the status of an SM Context of a PDU session (e.g. the SM Context is released within the SMF). |
Subscribe/Notify |
AMF |
|
Retrieve SM Context (NOTE 2) |
Retrieve an SM context of a PDU session: – from SMF, or from V-SMF in HR roaming scenarios, for 5GS to EPS mobility; – from SMF during I-SMF insertion or from I-SMF during I-SMF change/removal; – from V-SMF during change of V-SMF. |
Request/Response |
AMF, I-SMF, V-SMF, SMF |
|
Create |
Create a PDU session in the H-SMF in HR roaming scenarios, or in the SMF for PDU sessions involving an I-SMF. |
Request/Response |
V-SMF, I-SMF |
|
Update |
Update a PDU session in the H-SMF or V-SMF in HR roaming scenarios, or in the I-SMF or SMF for PDU sessions involving an I-SMF. |
Request/Response |
V-SMF, H-SMF, I-SMF, SMF |
|
Release |
Release a PDU session in the H-SMF in HR roaming scenarios, or in the SMF for PDU sessions involving an I-SMF. |
Request/Response |
V-SMF, I-SMF |
|
Notify Status (NOTE 3) |
Notify the NF Service Consumer about the status of a PDU session (e.g. the PDU session is released due to local reasons within the SMF). |
Subscribe/Notify |
V-SMF, I-SMF |
|
Retrieve (NOTE 2) |
Retrieve information from a PDU session context from the H-SMF for a HR PDU session, or from the SMF for a PDU session with an I-SMF. |
Request/Response |
V-SMF, I-SMF |
|
Send MO Data |
Send mobile originated data received over NAS for a PDU session |
Request/Response |
AMF |
|
Transfer MO Data (NOTE 4) |
Transfer NEF anchored mobile originated data received from AMF for a PDU session |
Request/Response |
V-SMF, I-SMF |
|
Transfer MT Data (NOTE 5) |
Transfer NEF anchored mobile terminated data received from NEF for a PDU session |
Request/Response |
H-SMF, SMF |
|
NOTE 1: This corresponds to the SMContextStatusNotify service operation defined in 3GPP TS 23.502 [3]. NOTE 2: This corresponds to the ContextRequest service operation defined in 3GPP TS 23.502 [3]. NOTE 3: This corresponds to the StatusNotify service operation defined in 3GPP TS 23.502 [3]. NOTE 4: This corresponds to the MessageTransfer service operation in clause 4.25.4 of 3GPP TS 23.502 [3]. NOTE 5: This corresponds to the MessageTransfer service operation in clause 4.25.5 of 3GPP TS 23.502 [3]. |
|||