Re: LLQ with Bandwidth MQC

Thanks to all for their time and explanation:

Let me ask it again please:

I have four class-maps (1,2,3,4) and under policy-map I use "bandwidth
percent 25" for the three classes 1,2,3.
Now for the class-map 4, I configure "priority percent 25".

My question is how Priority will be handled, will the traffic for class-map
4 get priority upto 25% of BW and how the traffic in class-map 1,2,3 and
default -class will be handled under congestion?

I have an impression that class 4 will get 25% (due to priority) and extra
traffic in this class will be dropped, class-maps 1,2,3 will get upto 25% of
BW as there is no additional BW available and they will get their minimum
share and traffic in default-class will be dropped as there is no BW
available. Can some one correct if wrong please?

On Wed, Nov 25, 2009 at 11:43 PM, Babatunde Sanda <sbabatunde1_at_ca.rr.com>wrote:

> I forgot to include the " max-reserved-bandwidth 80" under the serial
> interface
>
> INT S0/0
> max-reserved-bandwidth 80
> service-policy output INTERNET_TRAFFIC
>
>
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> sbabatunde1_at_ca.rr.com
> Sent: Wednesday, November 25, 2009 7:40 PM
> To: S Malik; ALL From_NJ
> Cc: Cisco certification
> Subject: Re: LLQ with Bandwidth MQC
>
> Hello Malik,
>
> Here is a quick QOS MQC run down (there is way more to QOS though). The
> command "max-reserve bandw" is to modify the default reserved bandwidth on
> interfaces which is 25% of the interface by default. This is needed for the
> "class-default" (any traffic not explicitly classified for in your
> configuration. So when you configure traffic with MQC you are actually
> using the remaining 75% on the interface. You shouldn't have to modify the
> reserved bandwidth except absolutely necessary because you definitely cannot
> classify for all traffic. If my memory serves me I think the maximum class
> recommended is 11 and minimum is 4. So you want to make sure there is
> bandwidth for this traffic's to use (As usual Cisco will give you the
> command to shoot yourself in the foot even though they recommend otherwise).
>
> When configuring LLQ, you use the command priority percent "bandwidth
> percent" or priority bandwidth "bandwidth amount". When you do this you are
> policing the class you specified to the amount in percentage or specified
> bandwidth amount. In other words this command is saying the traffic will
> not get more than the amount if congestion happens.
>
> On the other hand when you use the "bandwidth percent or bandwidth followed
> by the bandwidth amount" you are saying to the class "you get this amount
> if congestion happen and if there is more bandwidth and you need more you
> can use more.
>
> So for example say I want to classify for this 3 traffic voice, video and
> Gnutella and I want to use 80 percent of the total bandwidth on the
> interface I will do something like this.
>
> TRAFFIC CLASSIFICATION
>
> class-map match-any VIDEO
> match ip dscp 41
> class-map match-any VOICE
> match ip dscp ef
> class-map match-any TRASH
> match protocol gnutella
>
> ACTION
>
> policy-map INTERNET_TRAFFIC
> class VOICE
> set dscp ef
> priority percent 33
> class VIDEO
> set dscp 41
> bandwidth percent 10
> class TRASH
> set dscp af11
> bandwidth percent 2
> class class-default
> fair-queue
> random-detect dscp-based
>
>
> APPLICATION
>
> INT S0/0
> service-policy output INTERNET_TRAFFIC
>
>
> Hope this gives you a better insight and encourage you to read more on QOS.
>
>
> Good luck.
> ---- S Malik <ccie.09_at_gmail.com> wrote:
> > All,
> > I have deliberately configured three classes with BW statement under a
> > policy-map so that it consume 75% of BW.
> >
> > Fourth class I configured with priority %25. Now I could configure
> > service-policy out on interface by changing "max-reserve bw 76%.
> >
> > I think, BW 25% command under policy-map means minimum 25% and priority
> 25%
> > means upto 25%.
> >
> > What I like to confirm is that if I keep max-reserve BW 76% then only 1%
> of
> > BW will be used for LLQ?
> >
> > On Wed, Nov 25, 2009 at 11:39 AM, ALL From_NJ <all.from.nj_at_gmail.com>
> wrote:
> >
> > > If you have configured more bandwidth than what is avail, you will see
> the
> > > error message telling you that you do not have enough. You can use the
> > > max-reserv command to alter what is available for your configuration.
> > >
> > > The link:
> > >
> > >
> http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_m1.html#wp1039174
> > >
> > > By default you can only configure up to 75% of the bandwidth. Use this
> > > command when you want to configure more. In your example, 24% would
> still
> > > be available for class-default, aka ... unnamed traffic that does not
> match
> > > your class-maps.
> > >
> > > The percent command will be a percentage of the available bandwidth.
> The
> > > above link can also be used for looking up these commands as well.
> > >
> > > IMO, the percentage commands are very good when you are offering a
> service
> > > to another or when you want to standardize a QoS config.
> > >
> > > For example, network management traffic will always get at least 5% of
> the
> > > bandwidth or biz traffic will always get 40% of bandwidth etc ...
> > >
> > > Some service providers might offer different service levels at
> different
> > > prices. An example of these might look like:
> > >
> > > VoIP always get 25%
> > > Net Management always gets 5%
> > > Ip Prec 3 might always get 30%
> > > IP Prec 4 .... gets 15%
> > > etc ...
> > >
> > > If you are a service provider, you can apply these configs to any link
> and
> > > maintain the same service levels regardless of the actual bandwidth of
> the
> > > link. Voip will still always get 25% whether it is on a T1 or T3 ...
> > >
> > > Does this make sense? I hope my examples are clear (many times I
> confuse
> > > myself :-))
> > >
> > > HTH,
> > >
> > > Andrew Lee Lissitz
> > > .
> > > On Wed, Nov 25, 2009 at 11:18 AM, S Malik <ccie.09_at_gmail.com> wrote:
> > >
> > >> ALL,
> > >>
> > >> if I have three classes of traffic each with 25% of minimum BW and 4th
> > >> class
> > >> of traffic with priority percent 25 then all I need for the
> service-policy
> > >> command to go through under interface is "max-reserve bw 76%".
> > >>
> > >> My question is that in this case only 1% of BW will be allocated to
> the
> > >> traffic which is configured for LLQ?
> > >>
> > >>
> > >> Blogs and organic groups at http://www.ccie.net
> > >>
> > >>
> _______________________________________________________________________
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> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >
> > >
> > > --
> > > Andrew Lee Lissitz
> > > all.from.nj_at_gmail.com
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
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>
>
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Received on Thu Nov 26 2009 - 11:00:06 ART