Re: QOS on Catalyst 2960

Hi Irfan.
We are doing the same sort of marking in production (2960/3560/3750
access switches) but using dscp instead of cos, all works fine.

You can try and check show mls qus interface stat output for both
access-port and trunk port in question. You may be able to see some
helpful counters increasing there.

HTH
A.

On 7/24/2011 5:50 AM, Irfan Sid wrote:
> 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 Sun Jul 24 2011 - 22:28:59 ART