QCI 80 Support on UPF

Feature Summary and Revision History

Summary Data

Table 1. Summary Data
Applicable Product(s) or Functional Area 5G-UPF
Applicable Platform(s)

VPC-SI
Feature Default Setting Enabled – Always-on
Related Changes in this Release Not Applicable
Related Documentation UCC 5G UPF Configuration and Administration Guide

Revision History

Table 2. Revision History
Revision Details Release
First introduced. 2022.01.1

Feature Description

The 5G-UPF supports new standard QoS Class Index (QCI) 80 based on 3GPP TS 23.203, for establishing a non-GBR QoS flow when an application sends traffic to the specific destination.

How it Works

Dynamic QoS Flow Establishment based on Detected Traffic

To establish a dynamic QoS flow when traffic is detected, UPF uses the Application Detection and Control (ADC) over Gx feature.

On receiving a PCC predefined rule over default 5G QoS Identifier (5QI) for application detection and control, the SMF instructs the UPF to detect application traffic. The UPF installs the Gx ADC PDR with default QFI, and the rule name is considered as Application ID for reporting to the SMF.

On detecting a new flow hitting the Gx ADC predefined rule, the UPF triggers an Application Start event. When the application traffic is identified by an application identifier, the SMF reports the start of application to the PCF.

The PCF then makes policy decisions based on the information received and sends the corresponding updated PCC rules (with QCI-80) to the SMF.

Call Flow

The following figure shows the call flow details and the message exchanges in a 5G core system.

Step

Description

1

The PCF sends SmPolicyUpdateNotify to SMF, and receives an acknowledgment.

2

SMF activates the ADC rule (Predefined rule).

3

SMF maintains the predefined rule for Application ID mapping.

4

SMF sends the N4 Session Modification Request to UPF, and receives a response from UPF.

5

ADC is activated at the UPF.

6

UPF detects the packets matching ADC rule.

7

UPF sends the N4SessionUpdate request to the SMF, and receives a response from the SMF. UPF triggers Application Start.

8

SMF sends the SmPolicyUpdate Request to PCF, and receives an acknowledgment from the PCF. Optionally, the dedicated bearer is created as part of response.

9

PCF sends SmPolicyUpdateNotify to SMF, and receives an acknowledgment from SMF.

10

PCF sends dynamic rule for QCI 80 bearer, and a dedicated bearer is setup.

11

UPF switches the traffic to dedicated bearer.

12

UPF detects stop of traffic on dedicated bearer.

13

UPF sends the N4SessionUpdate request to the SMF, and receives a response from the SMF. UPF triggers Application Stop.

14

SMF sends the SmPolicyUpdate Request to PCF, and receives an acknowledgment from the PCF. Optionally, the dedicated bearer is removed as part of response.

15

PCF sends SmPolicyUpdateNotify to SMF, and receives an acknowledgment from SMF.

16

PCF sends removal of dynamic rule for QCI 80 bearer, and the dedicated bearer is removed.

Limitations

The following is the known limitation to this feature in this release:

  • Gx ADC predefined rule is installed only with default bearer 5QI.

Configuring ADC Rule

To support activation of predefined ADC rules, you must configure the ADC rule in SMF with appropriate action priority, and adc keyword. The following is a sample configuration: 

active-charging service service_name   
     rulebase rulebase_name  
            action priority action_priority dynamic-only adc ruledef ruledef_name charging-action charging_action_name  
     exit 
ruledef ruledef_name  
    ip server-ip-address ipv4/ipv6_address/mask 
    ip server-ip-address ipv4/ipv6_address/mask 
    exit 
exit

To mute the reporting, use the following CLI command under rulebase configuration:

action priority action_priority dynamic-only adc mute ruledef ruledef_name charging-action charging_action_name

To optimize the application reporting once per application, use the following CLI command under rulebase configuration:

adc app-notification once-per-app

To optimize the application reporting once per application per flow, use the following CLI command under rulebase configuration:

adc app-notification once-per-ipflow

NOTES:

  • rulebase rulebase_name : Enables the Active Charging Service Rulebase configuration

  • action priority action_priority : Assigns priority to a ruledef in the rulebase. Priority must be a unique integer value ranging 1–65535.

  • dynamic-only : Enables matching of dynamic rules with static rules for this action priority on a flow.

  • adc : Specifies the ruledef to-be given as ADC rule.

  • ruledef ruledef_name : Adds the specified ruledef to the current rulebase.

  • charging-action charging_action_name : Specifies the charging action.

  • description description : Adds specified text to the rule and action.

  • ip server-ip-address ipv4/ipv6_address/mask : Specifies the server IP address with subnet mask bit. For uplink packets (subscriber to network), this field matches the destination IP address in the IP header. For downlink packets (network to subscriber), this field matches the source IP address in the IP header.

  • once-per-app : Notifies APP_START or APP_STOP notification once per App ID.

  • once-per-ipflow : Notifies APP_START or APP_STOP notifications per App ID per IP flow.

Monitoring and Troubleshooting

This section provides information on CLI commands that are available for monitoring and troubleshooting the feature.

Show Commands to Display PDR and URR

Use the following command on UPF to display the PDR for which ADC is enabled:

show subscribers user-plane-only callid callid_value pdr full all

Use the following command on UPF to display the URR for which ADC is enabled:

show subscribers user-plane-only callid callid_value urr full all

Show Commands to Display ADC Statistics

Use the following command on UPF to display the ADC statistics:

show subscribers user-plane-only callid callid_value adc statistics