PTP820's removing DSCP markings used for QoS

Within our network we are using licensed PTP820's as backhauls between different areas of our site. We are having issues with them stripping dscp markings we are using for QoS.

Currently all our required markings are applied in the field, as close to the source as possible. We have monitored them being passed up to and including the switch trunk port connecting to the 820's. When we inspect the traffic on the switch port at the other end of the link there are no longer any dscp markings.

In the logical interface menu we have set Trust VLAN UP bits to "Trust", Trust DSCP to "Trust", Trust MPLS to "Trust" and Default port CoS to "0".

In the QOS menu, we have not changed any of the mappings, are not using a policer, or shaper, and have left the rest to defaults.

We have set the Ethernet Services Configuration table CoS mode to "Preserve-SP-COS-Decision", the Ingress Attribute CoS mode is "Interface-Decision", and the Egress Attributes CoS preservation and Marking Admin are "Enable".

We have more then sufficient bandwidth and are not overly concerned about QoS across this link, we do however require it for some of our end to end services that cross the WAN to ensure reliable delivery of critical data as it passes through other more congested areas.

I'm not super familiar with the PTP820's and I'm hoping I've just overlooked something here. Any help would be appreciated.

Please contact customer support.

See for information about contacting customer support.

I hope this helps!