Re: Policing in one class with LLQ

Roy,
I don't follow your NB.

When congestion "is not in play", there is no such thing as a
class-default queueing because there is no queueing at all.
What would be the gain of having priority if there is no packet
that has to wait for you ?
The nitty gritty is surelly architecture dependent, but in some
platforms that has to do with the TX-Ring having space to receive
the packet. Once you are there, you are set to be going "real soon now" :)

-Carlos

Roy Waterman @ 17/2/2010 8:34 -0300 dixit:
> Hi Dennis
>
> Yes you can, and as advised, you need to, if you wish the LLQ class to be
> policed at all times.
> The internal policer is only applied during congestion conditions.
> (Pretty much reiterating what is being said :) ).
> NB. LLQ class Traffic exceeding the value specified in the priority
> statement when congestion is not in play gets put into class-default, & is
> not priority "queued". As such, having the police statement as well the
> priority is generally seen as a good idea if you want all your LLQ class
> traffic to be priority "queued".
>
> Regards
> Roy
>
>
> On 17 February 2010 05:58, CCIE-Newbie <ccie_ka_at_gmx.de> wrote:
>
>> Hi,
>> thanks to all for the advice...
>>
>> So if I understand it right...there is an internal policer..._but_ I can
>> also configure my own police command inside the LLQ class ?!
>>
>> Dennis
>>
>> Am Dienstag, den 16.02.2010, 20:22 +1100 schrieb Dale Shaw:
>>> Hi Jared,
>>>
>>> On Tue, Feb 16, 2010 at 7:09 PM, Jared Scrivener
>>> <lists_at_jaredscrivener.com> wrote:
>>>> Unlike the bandwidth command, the priority command has an internal
>>>> policer stopping it from using up excess bandwidth on the link. The
>>>> example you describe is normally seen in accompaniment to the
>>>> bandwidth command, I believe.
>>> Deja vu?
>>>
>>> http://www.groupstudy.com/archives/ccielab/200911/msg01728.html
>>>
>>> :-)
>>>
>>> See the "Which Traffic Classes Can Use Excess Bandwidth?" section of
>>> this document:
>>>
>> http://www.cisco.com/en/US/tech/tk543/tk757/technologies_tech_note09186a0080103eae.shtml
>>> "The queueing system imposes an important exception to this rule with
>>> a priority class. [...] the offered load of a priority class is
>>> metered by a traffic policer. During congestion conditions, a priority
>>> class cannot use any excess bandwidth."
>>>
>>> "[...] it is important to understand that since the priority classes
>>> are policed during congestion conditions, they are not allocated any
>>> remaining bandwidth from the bandwidth classes. Thus, remaining
>>> bandwidth is shared by all bandwidth classes and class-default."
>>>
>>> "If a bandwidth or priority class should not exceed its allocated
>>> bandwidth during periods of no congestion, you can combine the
>>> priority command with the police command. This configuration imposes a
>>> maximum rate that is always active on the class."
>>>
>>> cheers,
>>> Dale
>>>
>>>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net