Re: 3560 SRR sharing bandwidth

It is not true that the PQ has unlimited bandwidth, it will use up to the allocated BW but no more... It is true that it gets serviced before any other queue though.

On Jun 27, 2010, at 8:14 AM, manoj nanda wrote:

> any way by default only dscp 40-47 are mapped to the queue 1 on a 2960
> switch (just checked), thinking should be the same on 3560;
> usng-mwr-h2-usw01#show mls qos maps dscp-output-q
> Dscp-outputq-threshold map:
> d1 :d2 0 1 2 3 4 5 6 7 8 9
> ------------------------------------------------------------
> 0 : 02-01 02-01 02-01 02-01 02-01 02-01 02-01 02-01 02-01 02-01
> 1 : 02-01 02-01 02-01 02-01 02-01 02-01 03-01 03-01 03-01 03-01
> 2 : 03-01 03-01 03-01 03-01 03-01 03-01 03-01 03-01 03-01 03-01
> 3 : 03-01 03-01 04-01 04-01 04-01 04-01 04-01 04-01 04-01 04-01
> 4 : 01-01 01-01 01-01 01-01 01-01 01-01 01-01 01-01 04-01 04-01
> 5 : 04-01 04-01 04-01 04-01 04-01 04-01 04-01 04-01 04-01 04-01
> 6 : 04-01 04-01 04-01 04-01
>
>
> On Sun, Jun 27, 2010 at 7:59 AM, Piotr Kaluzny <piotrk_at_ipexpert.com> wrote:
>
>> It then makes perfect sense to map only a particular set of traffic (e.g.
>> EF) to this queue.
>>
>> Regards,
>> Piotr
>>
>>
>> On Sun, Jun 27, 2010 at 9:40 AM, Matt Eason <matt.d.eason_at_gmail.com>wrote:
>>
>>> Yes that is correct. Once the priority-queue out command is applied Q1 has
>>> no bandwidth restriction.
>>>
>>> On Sun, Jun 27, 2010 at 8:21 AM, manoj nanda <mnanda62_at_gmail.com> wrote:
>>>
>>>> Guys: I am wondering if there is a way to police the traffic for the
>>>> priority queue (queue-1 in this case).For example, if we use
>>>> "priority-queue
>>>> out" in this configuration, how do we avoid starving of other queues.
>>> Based
>>>> on my reading it appears that the moment you put this command
>>>> "priority-queue out" Q-1 becomes the king and can use whatever bandwidth
>>> it
>>>> demands ignoring the shaping/sharing command !!
>>>> Any guidance will be greatly appreciated!
>>>> r/Manoj
>>>>
>>>> On Tue, Jun 22, 2010 at 6:31 PM, m.lammerse <m.lammerse_at_mac.com> wrote:
>>>>
>>>>> Hi Group,
>>>>>
>>>>> I'm trying to clarify my understanding of 3560 SRR shaping and
>>>>> sharing. If I have both configured, as per below:
>>>>>
>>>>> Switch(config)# interface
>>>>> gigabitethernet0/1
>>>>> Switch(config-if)# srr-queue bandwidth shape 8 0 0 0
>>>>> Switch(config-if)# srr-queue bandwidth share 4 4 4 4
>>>>>
>>>>> Will queues 2,3 and 4 be
>>>>> able to use bandwidth that is reserved for queue 1 if queue 1 doesn't
>>>> need
>>>>> it?
>>>>>
>>>>> I understand that queue 1 will be guaranteed and limited to 1/8 of
>>>>> 1Gbps. But what will be the bandwidth available for 2, 3 and 4? Is it
>>>>> 4/(4+4+4) * interface speed (1Gbps). Or is it 4/(4+4+4) * remaining
>>>>> bandwidth
>>>>> (1Gbps-125Mbps)?
>>>>>
>>>>> Best regards,
>>>>> Marcel
>>>>>
>>>>>
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>>
>>
>> --
>> Piotr Kaluzny
>> CCIE #25665 (Security), CCSP, CCNP
>> Sr. Support Engineer - IPexpert, Inc.
>> URL: http://www.IPexpert.com
>
>
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Received on Sun Jun 27 2010 - 08:36:29 ART