5.33 Support of enhancement of Edge Computing (for 5GC)
29.2443GPPInterface between the Control Plane and the User Plane nodesRelease 17TS
5.33.1 General
Stage 2 requirements for support of enhancement of Edge Computing are specified in 3GPP TS 23.548 [69].
5.33.2 Uplink packet buffering for low packet loss during EAS relocation
Support of uplink packets buffering for low packet loss during EAS relocation as specified in clause 6.3.5 of 3GPP TS 23.548 [69] is defined in clause 5.32.3.
5.33.3 Edge Relocation using EAS IP address and Port number Replacement
To support Edge Relocation using EAS IP address and Port number replacement as specified in clause 6.3.3 of 3GPP TS 23.548 [69], the SMF shall instruct the UPF to replace:
– for the UL traffic, the destination IP address and/or port number of the outgoing IP packet with the Target EAS IP address and/or port number, by provisioning an UL FAR with an IP Address and Port Number Replacement IE containing the Target EAS IP address and/or port number; and
– for the DL traffic, the source IP address and/or port number of the incoming packet with the Source EAS IP address and/or port number, by provisioning a DL FAR with an IP Address and Port Number Replacement IE containing the Source EAS IP address and/or port number.
A UPF that supports replacing the source and destination IP address and Port Number of an (inner) IP packet shall set the IPREP flag in the UP Function Features IE (see clause 8.2.25) and shall replace the source or destination IP address and/or Port Number of an (inner) IP packet as instructed by the SMF.
5.33.4 EAS Discovery procedure with Local DNS Server/Resolver
Clause 6.2.3.2.3 of 3GPP TS 23.548 [69] specifies two options (C and D) for scenarios where the DNS message is to be handled by a Local DNS server/resolver.
In Option C, the SMF shall provision UL PDR(s) on the UL CL (including e.g. the Local DNS server address) or the BP (e.g. with the source IP prefix set to the IP prefix address assigned by the Local PSA) and associated FAR(s) to route traffic destined to the L-DN including the DNS query messages to the L-PSA, as specified in clause 5.17.2.
In Option D, if the SMF has been configured that DNS Queries for an FQDN (range) query can be locally routed on the UL CL, the SMF shall instruct:
– the UL CL to locally route DNS queries for the FQDN (range) to the Local DNS server, by provisioning an UL PDR with one or more DNS Query Filters or with a pre-defined PDR matching the requested DNS traffic and by associating a FAR to the UL PDR to forward the traffic towards the Local PSA. A UPF supporting this option shall indicate that it supports steering DNS traffic based on the target domain of the DNS Query by setting the DNSTS flag in the UP Function Features IE (see clause 8.2.25); and
– the Local PSA to send the DNS traffic to the Local DNS server, by provisioning a UL PDR with one or more DNS Query Filters, as described above for the UL CL, and by associating a FAR to the UL PDR to forward the traffic to the Local DNS server via tunneling (with the FAR including the Outer Header Creation IE) or via IP address replacement (with the FAR including the IP Address and Port number Replacement IE containing the IP address and/or port of the Local DNS server).
5.33.5 Direct Reporting of QoS monitoring events to Local NEF or AF
A UPF may be instructed to report QoS monitoring events directly to a local NEF or AF as specified in clause 6.4 of 3GPP TS 23.548 [69].
A UPF that supports this feature shall set the DRQOS (Direct Reporting of QoS monitoring events) flag in the UP Function Feature IE (see clause 8.2.25).
An SMF shall instruct an UPF that supports the DRQOS feature to report Per QoS Flow Per UE QoS Monitoring events directly to a local NEF or AF by applying the requirements specified in clauses 5.24.4 or 5.24.5.3, and by additionally including a Direct Reporting Information IE in the SRR as specified in clause 5.2.8.2.
The Direct Reporting Information shall include the Event Notification URI towards which events shall be sent, and if available, the Notification Correlation ID to be included in these events. If the events need to be sent both directly to the local NEF or AF and to the SMF, the Direct Reporting Information IE shall also include the Reporting Flags IE with the DUPL flag set to "1".
An UPF that supports this feature shall send the Per QoS Flow Per UE QoS Monitoring events to the SMF if the SRR does not contain the Direct Reporting Information IE, or directy to the Local NEF or AF using the notification URI received in the Direct Reporting Information IE, or both if the Direct Reporting Information IE is provided with the DUPL flag set to "1", as specified in clause 5.24.4.3.
The UPF shall report QoS monitoring events directly to the Local NEF or AF using the UPF Event Exposure service specified in 3GPP TS 29.564 [73].