Transport Level Marking Options IE
The "Transport Level Marking Options" IE type is encoded as shown in the following figure. The DSCP for downlink transport-level marking is copied from the inner packet.

The Copy-Inner and Copy-Outer flags are present in bit-0 and bit-1 of octet 5. Copy-Outer flag is not used for downlink packets because there is no outer header present in packets coming from ISP. If a Copy-Inner flag is present, then the UPF uses DSCP value from the inner packet to mark the transport-level IP header.