OSPF - QoS/CoS Marking


Userlevel 3
Hi All.
I'm just wiresharking some OSPF traffic to check QoS markings and I notice that OSPF hellos generated by our Summit X460 are marked as DSCP CS6 but tagged as 802.1p priority 7.
We've got no QoS re-marking configured on the switch.
Can anyone explain the discrepancy and why the device doesn't use 1 to 1 class marking?
Many thanks....

5 replies

Userlevel 6
Hello Stephen

If you do a show do see a qosprofile assigned to that VLAN?

Thanks
P
Userlevel 3
thanks for your reply Paul.

extract from a 'show vlan '....

"QosProfile: None configured"
Userlevel 3
DSCP CS6 is a layer 3 marking
802.1p priority 7. is a Layer 2 Marking
as they are different methods there is no defacto requirement for them to match.
Simon Bingham ( alternative networks )
Userlevel 3
Yes of course, thanks Simon. I understand that but, in the absence of a QoS policy, I thought it was standard practice to mark CoS the same as the DSCP CS.
Userlevel 3
802.1p 7 is called Network Control so that would make sense and CS6 is the same value used by Cisco for protocol traffic so that might be why the values don't match. But as said I don't think they have to.

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