I'm trying to set up our network so the VOIP traffic has priority. The core is a 5412zl switch, subsidiary closets have 2920s. I set qos priority 7 on our VOIP vlan, 8, on all switches. I mirrored the uplink port on on one of the 2920s switches to another port, connected a laptop with Wireshark to the mirror port, examined the traffic on vlan 8. It's priority 7, as i expect. I then went to the main closet, mirrored the port that's the other end of that 2920 uplink, captured all the vlan 8 traffic and examined the priority. Regardless of how I've configured the priority in the 5412zl, I would expect to see vlan 8 traffic say it's priority 7. It doesn't. Traffic to the 2920 all says priority 1, the traffic from the 2920 all says it's priority 0. This is the same traffic, just being mirrored by a 5412 instead of a 2920. So the only explanation I can think of is the 5412 doesn't preserve the vlan tags' priority bits when it mirrors the port. Has anyone seen this before? Does anyone have any alternative explanation? Is there some setting you need in the 5412 config that I'm missing?
Any advice would be greatly appreciated.
Here's the vlan 8 config on the 5412, if it's important:
vlan 8
name "Mitel phone system"
tagged B1-B8,D1-D8,F1-F24
untagged A2,A4,E2,E4
ip address 10.11.7.254 255.255.252.0
qos priority 7
exit
and on a 2920
vlan 8
name "Mitel"
tagged 48,A1-A2
no ip address
qos priority 7
exit