QoS: I need to configure a port untagged, and the ingress and egress packet could be COS 6 and TOS 32

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I have an untagged port, and I need to do QoS on this port.
the packet in ingress and egress from this port could have COS=6 and TOS =32.

test(su)->show port egress ge.1.3
Port Vlan Egress Registration
Number Id Status Status
------------------------------------------------------------
ge.1.3 1 untagged static
!
set cos setting 8 priority 6 tos-value 32
set policy profile 2 name "Centrale-2" cos-status enable cos 8
set policy port ge.1.3 2
!

I sniff the traffic on this port (source)

with this configuration I see the packet from source to destination without COS/TOS
and the packet from destination to source with COS/TOS

from Wireshark:
Differentiated Services Field: 0x20 (DSCP 0x08: Class Selector 1; ECN: 0x00)

I'd like to undestand if the configurazione could be modify or is this the normal for an untagged port

thx
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Posted 5 years ago

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Tom Currier, Employee

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If I understand your question correctly, the behavior that you're seeing is normal for an untagged vlan. Using policy you may assign CoS values of 802.1p priority and ToS as you've demonstrated in your example. That traffic will be processed through the transmit queues of the switch according to the priority mapping. However, only ToS will be forwarded to the next hop on an untagged packet. Tagged egress is required for the 802.1p priority value to be included in a forwarded frame.
Thanks Thomas! is the config that i posted the correct way to do it or there're other way?
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Tom Currier, Employee

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Yes, your example is correct. You'll want to make sure that CoS is enabled on the switch in order to write the ToS and priority values to your tagged packets egressing the switch. You can enable this in Netsight Policy Manager's General tab for the device or via command line on the switch with the "set cos state enable" command.