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QoS switch config + mitel phones


Has anyone had any experience configuring QoS on catylst switches for Mitel phones?  I am hoping to classify voice traffic using COS 5(as per cisco phones).

The mitel 5220 phones support CDP, so I have configured my test switch port as follows.

interface FastEthernet0/29

description Test User - Phone & PC

switchport access vlan 19

switchport voice vlan 20

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape  10  0  0  0

mls qos trust device cisco-phone

mls qos trust cos

no snmp trap link-status

auto qos voip cisco-phone

spanning-tree portfast

spanning-tree bpduguard enable


I have setup monitoring of the port, and according to wireshark the mitel phones are passing DSCP 44, but not passing any COS tags.

On the DHCP server the there is a scope option that sets 'priority 6', but this doesn't seem to translate to COS that I can see.

I have tried to setting 'mls qos cos 5' and  'mls qos cos override', but still I can't see any COS markings received either on the Test User port, or the destination phone port.

Anyone got any thoughts?

  • Voice over IP