3GPP 23.501 v20.2.0 — the document's own text
5.7.7.2 PDU Set Delay Budget
Taught in 14. What the network promises (The 5G system architecture, in depth), 23. Very fast, very reliable, very picky (The 5G system architecture, in depth), 5. The connection, and what is promised on it (The 5G system architecture, overview).
The PDU Set Delay Budget (PSDB) defines an upper bound for the delay that a PDU Set may experience for the transfer between the UE and the N6 termination point at the UPF, i.e. the duration between the reception time of the first PDU (at the N6 termination point for DL or the UE for UL) and the time when all PDUs of a PDU Set have been successfully received (at the UE for DL or N6 termination point for UL). The DL PSDB applies to the DL PDU Set received by the PSA UPF over the N6 interface and the UL PSDB applies to the UL PDU Set sent by the UE.
NOTE 1: To enable support for PSDB, it is required that a maximum inter arrival time between the first received PDU and the last received PDU of a PDU Set complies with SLA. This maximum inter arrival time does not exceed PSDB. 5G-AN behaviour when the SLA is not fulfilled is out of scope of this specification.
A QoS Flow is associated with at most one PSDB value per direction. PSDB is an optional parameter that may be provided by the PCF. The provided PSDB can be used by the 5G-AN to support the configuration of scheduling and link layer functions.
When the PSDB is available, the UL and/or DL PSDB supersedes the PDB in the respective direction for the given QoS Flow in the 5G-AN.
NOTE 2: See clause 5.7.7.1 for dependency between PDU Set QoS parameters.
The AN PSDB is derived at 5G-AN by subtracting CN PDB (as described in clause 5.7.3.4) from the PSDB.