Using an older 5406zl (FW K.15.18.0015), I'm seeing QoS behavior that I don't believe is correct. This is a fairly simple setup - a Polycom VoIP phone connected to the 5406zl switch and the switch connected to the edge router.
Ports D14, B19 on the switch are assigned to VLAN 10, along with the VVX311 and eth4 on the firewall.
The intent is to have the switch assign a DSCP to all traffic on VLAN 10, overwriting the DSCP value from the VVX311 config. For testing I set the VVX311 to a DSCP value of 26 (AF31) and a 802.1Q value of 3.
On the switch, type-of-service is set to Differentiated Services
HP-5406zl# show qos type-of-service
DSCP-based Prioritization : Differentiated Services
and vlan-priority is configured (no other classifiers are configured)
HP-5406zl# show qos vlan-priority
VLAN-based Prioritization
VLAN ID Apply rule | DSCP Priority
------- ----------- + ------ -----------
1 No-override | No-override
2 No-override | No-override
3 No-override | No-override
10 DSCP | 101110 5
With the configuration I would expect all traffic leaving port B19 on the switch to have a DSCP value of 46 and 802.1Q priority set to 5. When I do a packet capture on eth4 on the firewall however, the DSCP value is unchanged from what is set on the phone. Also, the 802.1Q PRI value is changed to 4.
For comparison here's a capture directly from the phone eth0 interface before the packet gets to the switch:
As you can see the DSCP is not changed by the switch but the PRI field is. According the Advanced Traffic Management Guide for this switch, the DSCP value should be overwritten.
Is this an issue of me lacking understanding of how this should work or is there a technical problem here?
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Chris McFarling
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