Re: mls qos cos override and the likes

so if a frame comes in with a cos value of 5

interface fa0/1
mls qos trust cos
mls qos cos 3

with the above config *...it retains cos of 5*

the same frame with cos of 5 . when arrives on interface with below config

interface fa0/1
mls qos cos 3
mls qos cos override

*it get a new cos value of 3 .....*
**
**
is this correct ?

thanks
On Fri, Sep 9, 2011 at 10:53 AM, Pavel Bykov <slidersv_at_gmail.com> wrote:

> Emir, yes, like Adam described,
>
> the "mls qos cos" command is the "Fallback COS" or what marking should a
> packet be assigned if the switch is confused and does not know what to do.
> Examples of that is that you receive untagged traffic (access port, or
> native vlan on a trunk port). In case the trust would be "mls qos trust
> DSCP", the setting would also apply to all non-IP traffic, like IPX, LOOP,
> DTP, VTP, CDP, STP, etc.
> The "mls qos cos override" command is the highest priority command, that
> makes everything behave according to the set cos, no matter the
> trust/service-policy settings.
>
> The list of what takes precedence is the following:
>
> mls qos cos override
> service policy
> mls qos trust
> mls qos cos
> Pavel
>
> On Fri, Sep 9, 2011 at 12:16 AM, emir d souza <emir979_at_gmail.com> wrote:
>
> > Hi Guys,
> >
> > I'm a bit confused with the combination of commands for mls qos on an
> > interface. The objective is to mark all incoming packets on that
> interface
> > with a cos marking of 3.
> >
> > What's the difference between
> > interface fa0/1
> > mls qos trust cos
> > mls qos cos 3
> >
> >
> > and
> >
> >
> > interface fa0/1
> > mls qos cos 3
> > mls qos cos override
> >
> >
> > and if you have both override and trust cos, which one will take
> > precedence?
> > Pls don't send me a Cisco link, the explanation from there is confusing.
> >
> >
> > Cheers!
> >
> >
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>
> --
> Pavel Bykov
>
>
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Received on Sat Sep 10 2011 - 09:52:00 ART