Protocol Data Unit

In Release 15, key enhancements for the PDU function included the introduction of a new **PDU Session type IPv4v6** and the addition of a **DNN object** within the PDU session establishment parameters. Furthermore, the release specified UE support for **Multi-homed IPv6 PDU Sessions** and provided clarifications for **Ethernet Type PDU Sessions**, including aspects like MTU and traffic routing.

• Addition of PDU Session type IPv4v6 TS 23.501CR0181
• TCP protocol as inner transport layer protocol for NAS signaling TS 24.502CR0040
• Call Control update for PDU sessions TS 31.111CR0683
• Addition of DNN object in PDU session establishment parameters TS 31.111CR0705
• Introduction of PDCP duplication TS 38.323CR0009
• Configuration information the UE may exchange with the SMF during the lifetime of a PDU Session TS 23.501CR0003

+ 71 more changes

In Release 16, key enhancements for the PDU function centered on the formalization and refinement of the Multi-Access (MA) PDU Session. This introduced new capabilities for traffic switching and QoS handling for Guaranteed Bit Rate flows within MA PDU sessions, alongside support for associating URLLC traffic to redundant PDU sessions. The release also provided clarifications and corrections for SMF, UPF, and PCF selection procedures specific to these MA PDU sessions.

• QoS for Multi-Access PDU Session TS 23.501CR0770
• Protocol stack for W-5GAN support TS 23.501CR0961
• Clarification on MA PDU session TS 23.501CR1033
• Subscription Information Influence on PDU Session Rate Control TS 23.501CR1251
• Handling of Stored Small Data Rate Control Status at Subsequent PDU Session Establishment TS 23.501CR1252
• 23.501 part of PCF selection for PDU sessions with same DNN and S-NSSAI TS 23.501CR1375

+ 82 more changes

In Release 17, key enhancements to the PDU function included the introduction of restricted PDU Sessions for remote UE provisioning via the User Plane and the support for redundant PDU Sessions for URLLC with associated NGAP parameter corrections. The release also expanded Multi-Access PDU Session handling to include connectivity over E-UTRAN/EPC combined with non-3GPP access to the 5G Core, and clarified procedures for PDU Sessions used for Emergency services.

• MA PDU sessions with connectivity over E-UTRAN/EPC and non-3GPP access to 5GC TS 23.501CR2527
• Enabling restricted PDU Session for remote provisioning of UE via User Plane TS 23.501CR2709
• Clarification on UE provides PDU Session Pair ID based on URSP rules TS 23.501CR2736
• KI#3B, Resolving EN for Future PDU Session TS 23.501CR2791
• Support of RSN and PDU Session Pair ID in the URSP Rule TS 29.525CR0181
• PCF checking of redundant PDU session applicability TS 29.525CR0184

+ 30 more changes

In Release 18, key enhancements for the PDU function included the introduction of **PDU Set-based handling** and QoS management, enabling more efficient group-based operations. The release also added support for graceful termination of PDU sessions during network slice decommissioning and expanded Multi-Access PDU (MA-PDU) session capabilities, including interoperability with EPC. Furthermore, it introduced mechanisms for changing the PDU Session Type for a group of UEs and optimized time validity policies for network slices.

• The support of Home Routed PDU Session supporting Session Breakout in VPLMN (HR-SBO) TS 23.501CR3830
• Change of Network Slice instance for PDU sessions TS 23.501CR3867
• Support non-3GPP access leg of MA-PDU Session with PDN connection in EPC TS 23.501CR3937
• KI#3, NEF exposure for handling PDU Session Type change and managing temporal invalidity/validity condition for a group of UEs TS 23.501CR3964
• Optimizations for the support of time vality policies for a network slice and graceful network slice PDU sessions release. TS 23.501CR4004
• Support of PDU Set based handling TS 23.501CR4046

+ 58 more changes

In Release 19, key enhancements for the PDU function introduced the concept of "PDU Set" handling to improve QoS for specific traffic types, such as encrypted XR media over MoQ or connect-UDP. This included leveraging PDU Set QoS information for DSCP marking over the N3 and N9 transport interfaces and extending PDU Set-based handling to non-3GPP accesses. Furthermore, the release provided architectural clarifications and enhancements for Backhaul (BH) PDU Sessions involving the MWAB node, including NAT functionality in the UPF.

• Control Plane and User Plane Protocol stacks involving the MWAB node TS 23.501CR5561
• General description of relaying media related information over N6 using an encapsulation protocol TS 23.501CR5711
• Support PDU Set information identification based on MoQ for encrypted XRM traffic TS 23.501CR5632
• PDU Set Information Identification for end-to-end encrypted traffic using connect-UDP - architecture part TS 23.501CR5728
• MWAB BH PDU session clarification TS 23.501CR5828
• Leveraging PDU Set QoS information for DSCP marking over N3/N9 in the transport network TS 23.501CR5407

+ 40 more changes

In Release 20, the PDU function was updated to support Ethernet type Backhaul PDU Sessions for Mobile Wireless Access Backhaul (MWAB). It also introduced corrections for Energy Consumption calculations in scenarios involving redundant transmission or sessions with multiple PDU Session Anchors. Furthermore, the release included fixes for mistakes related to PDU Set based handling and PDU Set based QoS handling.

• Support of Ethernet type of BH PDU Session for MWAB TS 23.501CR6330
• Correction on Energy Consumption calculation for redundant transmission or PDU Session with multiple PDU Session Anchors TS 23.501CR6522
• Fix the mistake of PDU Set based handling and PDU Set based QoS handling TS 23.501CR6526