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Bug Report: Tagged VLAN traffic has PCP/CoS field set to 5

oreo
New Contributor

Reference: https://en.wikipedia.org/wiki/IEEE_802.1Q. The PCP field is also known as priority / class-of-service.

This is happening on all tagged VLAN traffic, including ARP packets. I tried two switches: an ICX 6450 and an ICX 7250.

Using `ip pcp-remark 0` on the VE interface corrects all traffic except ARP.

This is a very strange behavior -- possibly a bug? Can someone else confirm this?

6 REPLIES 6

oreo
New Contributor

No, I am talking about the 802.1Q frame of an Ethernet packet. With the above configuration, a packet within VLAN 210 going out of interface 1/1/1 has the priority field set to 5, which is unexpected.

Chandini
RUCKUS Team Member

Hi Orea 

Understood. As per the below link ICX switches decide a packet’s priority by checking several things in order. First, they look for an ACL that sets a priority. If not found, they check if the packet’s MAC address matches a static entry with a set priority. If neither applies, they use the default priority of the incoming port, then check the DSCP/ToS value, followed by the 802.1p CoS value. If none of these are set, the packet gets a default priority of 0 as per the link below.

I recommend opening a support case with us so we can assist you further. We'd be happy to work with you to verify the CoS value you're observing in the 802.1Q Ethernet frame header.

Thank you