[c-nsp] catalyst 6500 not rewriting CoS / 802.1p bits

[Peter Rathlev]

Hi Vladimir,

The "mls cos cos 5" command is only used for frames without an
existing .1p tag, like frames from the native VLAN in a trunk or frames
from an access port.

I think the Cat6500 has the "override" keyword, so you can add the line
"mls qos cos override", which should do what you want, i.e. setting CoS
5 for all packets arriving at the port.

IMHO a service policy would be the best way to do it though, as Arie
mentions.

Regards,
Peter


On Sun, 2008-02-10 at 00:31 +0200, Vladimir Ivashchenko wrote:
> Hi List,
> 
> We cannot get Cat6500 to rewrite CoS values (802.1p bits).
> 
> Configuration is 
> 
> mls qos
> no mls flow ip
> no mls flow ipv6
> no mls qos rewrite ip dscp
> no mls acl tcam share-global
> mls cef error action freeze
> 
> interface GigabitEthernet2/1
>  switchport
>  switchport trunk encapsulation dot1q
>  switchport mode trunk
>  no ip address
>  load-interval 30
>  wrr-queue queue-limit 40 30
>  mls qos cos 5
>  no cdp enable
>  spanning-tree portfast trunk
>  no mls qos trust
> 
> We have a sniffer connected to dot1q trunk on another port. The sniffer shows that 802.1p value for packets going out 
> from Gig2/1 is set to 0. We have tried searching Cisco site and playing with various commands, but did not succeed. IOS  
> 12.2(18)SXF5.
> 
> Catalyst 3560 has "mls qos cos override" command, which seems to do the trick, but this command is not available on 
> Catalyst 6500.
>