2950 switch - mls qos - NOT removing COS/DSCP values?

[brettp]

I am just now diving into COS/QOS and right away, I'm not getting far :( I am messing around on a 2950 switch. Based on what I read, when I enable "mls qos," any marked traffic entering the switch would have those values changed to 0. Is that correct? I have an Avaya VOIP phone attached that marks the DSCP value 46. When I use wireshark and capture that traffic (again, there is no other config on the switch except mls qos,) the DSCP value is still 46!? I thought it would be 0? Any ideas?

mls qos

interface fastethernet0/1

switchport access vlan 110

switchport mode access

switchport voice vlan 112

show mls qos

QoS is enabled

QoS ip packet dscp rewrite is enabled

[Joseph W. Doherty]

The general rule on most old(er) Cisco switches, if QoS is enabled, if the port doesn't "trust", the swtich resets CoS and/or ToS to zero.

However, that's a general rule. For how your 2950 should behave, you would need to read the documentation that applies to that particular model and its running IOS version vs. how it's configured.

[brettp · Accepted solution]

I'm not afraid to show I'm an idiot... I'm back to post what the issue was. I was running wireshark and sniffing the ingress interface (duh!) thus I was seeing the marked traffic. I should have been sniffing the egress interface after the switch remarked the traffic.