2960 and Qos : It doesn t work

[gbusson]

Hi,

trying to set up Qos on a 2960. What i want to do : Tagging port Fa0/4 to Cos 5

I've done this with 2950 EI but it doesn't work witch 2960

Here's my configuration

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

mls qos

interface FastEthernet0/4

description *** MEDIA GATEWAY RTP ***

switchport access vlan 11

switchport mode access

switchport nonegotiate

speed 100

duplex full

mls qos cos 5

mls qos trust cos

spanning-tree portfast

end

I monitor port Fa0/4 and all trames have dscp 0

What is wrong in my configuration ? same configuration works with 2950.

Thanks

[h.parsons]

The show policy-map interface command does not work on the 2960 and other switches, so as you can see it is hard to see what is actually going on.

[gbusson]

Ok thanks. But what is wrong in my configuration ?

[Edison Ortiz]

As another poster suggested, why don't you start with "AutoQoS" as a baseline and then modify per your needs.

Take a moment and read the link that I and the other poster have referred you to go.

I don't have a 2960 switch at the moment to verify the correct configuration and as you can see, every hardware have a slightly different QoS configuration.

HTH,

__

Edison.

[gbusson]

Hi,

i've have tried to use autoqos. No more success

[mauricio.rodriguez]

Hi,

You cannot "trust" the CoS and force the CoS at the same time.

You have to choice between trust or force the cos.

In your configuration, you have to remove the command "mls qos trust cos".

If it is possible, try to force with DSCP and not CoS with the command "mls qos dscp 46" but I don't know if it works on 2960.

Best regards

[lgijssel]

You cannot do "trust cos" in this setup. The port has been configured as an access port and thus will not have a dot1Q header. As the cos-bits are in the 802.1p section of this header, the switch will read the cos as '0' and clear the dscp-field because of the trust. That is for incoming traffic (i.e. from the MGC)

Traffic towards the MGC (outgoing from the switch)should have had it's qos set at entering the network. Non-trusting ports and trunks will wipe this information, resulting in the delivery of class0 traffic.

When the MGC does not send traffic with correct markings you may apply these on the switch but I would rather go for trusting what is sent. This means that you should trust dscp and configure the MGC to mark the traffic.

regards,

Leo