QOS on Catalyst 2960

cisco Qos is good in theory, but a pain in practice. please help :(

I have a 2960 Catalyst switch with LAN Base.I have set my inbound cos value
to be a configurable value of cos 3 on fa0/2 (to mark all inbound frames). I
understand from Cisco documentation, that this COS value will not be written
into the Ethernet frame, but used to derive an *"Internal"* DSCP value or
QOS Label if you will. This internal DSCP is derived from the COS-DSCP map,
which in my case maps Cos3 to DSCP 24. (cs3)

This internal DSCP value of 24 should then be written back to a COS value
if the outgoing interface is a trunk based on the DSCP-COS Map. In my case
which is using the default mapping of DSCP 24 being mapped to Cos 3. However
when I run a packet capture on the outgoing interface, I do not see the
frame marked with Cos 3.

Below is my configuration, please can you advise....

mls qos map cos-dscp 0 8 16 24 32 46 48 56

mls qos

!

interface FastEthernet0/1

switchport mode trunk

!

interface FastEthernet0/2

switchport access vlan 100

mls qos cos 3

mls qos cos override

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Received on Sat Jul 23 2011 - 22:50:09 ART