Re: MLS QOS: 3560 vs 3550

Jack,
> i think i have seen this before, even with the 3560. try this:
>
> - on the 3550, issue the command :"sho mls qos". based on your config
> so far, it should display something like:
> - QoS is enabled (assuming you did issue "mls qos" prior)
> - QoS ip packet dscp rewrite is enabled (this is by default)
>
> the 2 bullets above mean that once you enable Qos, ,any packet traversing
> the switch will be rewritten to dscp=0. so all yo need to do to achieve your
> results is to just disable the global dscp rewriting, and the global command
> for that is "NO mls qos rewrite ip dscp". if your 3550 supports this
> command, then you should be golden. let us know what happens
>
>
> Jep.
>
>
> On Fri, Jan 22, 2010 at 11:54 AM, Mark Cairns <m.a.cairns_at_gmail.com>wrote:
>
>> Are you trying to trust DSCP on the interface or are you trusting DSCP
>> within the class used to define traffic for your policy? Sorry I don't
>> have
>> a 3550 in front of me. I believe you can have mls qos trust dscp on the
>> interface or "trust dscp" in your class. Try the second one.
>>
>> Mark
>> #17755, Security
>>
>> On Thu, Jan 21, 2010 at 12:23 PM, Jack Router <pan.router_at_gmail.com>
>> wrote:
>>
>> > Responded too quickly.
>> > "mls qos trust dscp" and "service-policy input TST" cannot co-exist on
>> the
>> > same interface. When one command is entered the other command is
>> > automatically removed.
>> >
>> >
>> > -----Original Message-----
>> > From: Jack Router [mailto:pan.router_at_gmail.com]
>> > Sent: 21-Jan-10 11:39
>> > To: ron.wilkerson_at_gmail.com; ccielab_at_groupstudy.com
>> > Subject: RE: MLS QOS: 3560 vs 3550
>> >
>> > Yes there is one and it works. Thanks.
>> >
>> > -----Original Message-----
>> > From: ron.wilkerson_at_gmail.com [mailto:ron.wilkerson_at_gmail.com]
>> > Sent: 21-Jan-10 11:29
>> > To: Jack Router; ccielab_at_groupstudy.com
>> > Subject: Re: MLS QOS: 3560 vs 3550
>> >
>> > Isn't there a trust dscp command on the 3550?
>> > -----Original Message-----
>> > From: "Jack Router" <pan.router_at_gmail.com>
>> > Date: Thu, 21 Jan 2010 11:05:03
>> > To: <ccielab_at_groupstudy.com>
>> > Subject: MLS QOS: 3560 vs 3550
>> >
>> > Hello,
>> >
>> > I am testing policing. Here is diagram:
>> >
>> > R1--\
>> > 3560(f0/19)----trunk----(f0/19)3550(f0/3)-----R3
>> > R2--/
>> >
>> >
>> > I am policing traffic from R1,R2 to R3
>> > R1 sends packets marked DSCP 10
>> > R2 sends packets marked DSCP 20
>> > Policy map is applied on 3550 int f0/19:
>> >
>> > Policing seems to work because I can see ping drops on R1 or R2 as soon
>> as
>> > service policy is applied on 3550, int f0/19.
>> > My problem is that 3550 rewrites all dscps to 0 as soon as mls qos is
>> > enabled. On 3560 I can disable dscp rewrites with command "no mls qos
>> > rewrite ip dscp" but on 3550 there is no such command.
>> >
>> > Is there a way not to rewrite DSCPs on 3550 so R3 will receive packets
>> as
>> > marked by R1 and R2?
>> >
>> > I know that there is no 3550 on the lab anymore but just want to
>> understand
>> > how
>> > this works...
>> >
>> > Thanks,
>> >
>> >
>> > Blogs and organic groups at http://www.ccie.net
>> >
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Received on Sun Jan 24 2010 - 22:26:55 ART