The possibility to use mls qos trust dscp with service-policy

[mhiyoshi]

Hello

I would like to know the possibility to use mls qos trust dscp with service-policy in the IOS ver.12.2(25)SEE2.

The specific version is not possible to configure like below.

Cat3750(config-if)#do sh run int f1/0/1

Building configuration...

Current configuration : 55 bytes

!

interface FastEthernet1/0/1

mls qos trust dscp

end

Cat3750(config-if)#service-policy input TEST

Cat3750(config-if)#do sh run int f1/0/1

Building configuration...

Current configuration : 62 bytes

!

interface FastEthernet1/0/1

service-policy input TEST

end

Cat3750#sh ver

*omit

Switch   Ports  Model              SW Version              SW Image

------   -----  -----              ----------              ----------

*    1   26     WS-C3750-24P       12.2(25)SEE2            C3750-IPSERVICES-M

Also, other version can possible to do this.

So I would like to know this is just only happen to this version.

Best Regards,

Masanobu Hiyoshi

[Edison Ortiz]

Under a class, you use the syntaxt 'trust dscp'

For instance:

service-policy input TEST

     class class-default

          trust dscp

[mhiyoshi]

Is it possible to configure as follows in the IOS ver.12.2(25)SEE2?

!

interface FastEthernet1/0/1

service-policy input TEST

mls qos trust dcsp

Best Regards,

[Edison Ortiz]

Yes.

What's inside the policy-map?

The port is set to trust dscp but if you have anything in the policy-map, it may alter the QoS behavior.

[mhiyoshi]

Yes the policy-map is below

policy-map TEST

class class-default

  trust dscp

[Edison Ortiz]

Having the service-policy on the interface should be enough.
Having both features doing the same seems redundant

[mhiyoshi]

Thank you for your quick reply.

Well, I think there are two possibilities.

The one is

policy-map TEST

class class-default

  trust dscp

!

interface FastEthernet1/0/1

service-policy input TEST

mls qos trust dcsp

The other is

policy-map TEST

class class-default

  trust dscp

!

interface FastEthernet1/0/1

service-policy input TEST or  mls qos trust dcsp

So , I would like to know whether this depends on software version or not.

At least IOS ver.12.2(25)SEE2 can be configure only one possibiility.

For example if service-policy input TEST is configured then mls qos trust dscp can be disabled vice versa.

Best Regards,

[Edison Ortiz]

Both can be configured - you will see both in the running configuration.

However,  the feature applied last will be the one to take effect

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_55_se/configuration/guide/swqos.html#wp1032145

[Kentse Mogana]

Hi Edison,

I just went through that link and saw this:

   Classifying, Policing, and Marking Traffic on Physical Ports by Using Policy Maps

"A policy-map and a port trust state can both run on a physical interface. The policy-map is applied before the port trust state."

Does this mean that is really does not depend on the order of the commands?

Regards

Kentse.