DSCP Markings for 4G Collapsed Datapath Calls

For collapsed Datapath calls:

  • On Sxa leg, DSCP marking is sent in FAR from SGWC/Cn-SGWC.

  • On N4 leg, DSCP marking is sent in FAR from SMF.

  • For uplink packets, UPF applies the DSCP marking as per SMF configuration.

  • For downlink packets, UPF applies the DSCP marking as per SGWC/Cn-SGWC configuration in GTPU header.

  • For inner packet, DSCP marking is as per SMF configuration.

The SMF configuration/logic of sending the DSCP marking is similar as PGW-C. In case of the DSCP marking for the ECS charging action, priority is given to the charging action configuration for inner packet DSCP marking.