Re: OT : IOS XR QOS using priority/LLQ without policing

Dear Ahmed,

Answer as remembered based on discussion with Cisco TAC are interleaved.
Experts can correct me if I am wrong.
.

On Tue, Apr 28, 2009 at 2:25 PM, Ahmed Elhoussiny <aelhoussiny_at_gmail.com>wrote:

> Thanks Irfan,
> So what do you think will happen if i used the priority cmd only + the
> bandwidth cmds on other queues
> I mean the same configuration in my previous mail without the priority
> cmd..
>

I think you mean without police command. At the time of congestion it will
starve other classes as you have not mentioned any cap on the priority
queue.

>
> Will this enable dynamic LLQ BW allocation , and on the same time will
> reserve min BW for other queue, OR will the LLQ starve the whole BW in case
> of conguestion. ?
>

Same as above but need experts confirmation.

Another idea would be to use a non-llq class for voice.The queuing
algorithm is intelligent enough to provide near-llq behaviour even if you
don't use a priority queue.

Regards

Irfan Azhar
CCNA,CCIP...

>
> Thats my problem, there isnt any shiity simulator for teh IOS XR till now ,
> but im sure there will b asa teh CCIE SP track start inttoducing this
> devices by 2010 :P
>

>
> Thanks & B.regards
> Ahmed Elhoussiny,CCIE # 21988
>
> On Tue, Apr 28, 2009 at 10:05 AM, Irfan Azher <irfanazher_at_gmail.com>wrote:
>
>> I faced same issue as GSR/CRS-1 routers don't support congestion aware
>> policing and have no 'priority percent' option therefore I have used
>> strict police command with priority as mentioned in your DSCPEF class.
>>
>>
>> Best Regards
>>
>> Irfan Azher
>> CCNA,CCIP....
>>
>> On Mon, Apr 27, 2009 at 4:49 PM, Ahmed Elhoussiny <aelhoussiny_at_gmail.com>wrote:
>>
>>> Dear all,
>>> Hope your doing great, i would like to know if any one
>>> experienced or tried this before, or tried it, as tehre isnt an IOS XR
>>> simultaor as far as i know.
>>>
>>> I have designed the following QOS policy based on customer requirement
>>> &
>>> inputs.
>>>
>>> cmds are on GSR/CRS-1 IOS-XR ver 3.6.1
>>>
>>>
>>> int gix/y/z
>>>
>>> max-reserved-bandwidth 90
>>>
>>> service policy output *PE-OUT*
>>>
>>>
>>>
>>> policy-map *PE-OUT*
>>>
>>> class DSCPEF
>>>
>>> set ipv4 dscp ef
>>>
>>> *police rate percent 25*
>>>
>>> conform-action transmit
>>>
>>> exceed-action drop
>>>
>>> priority
>>>
>>> !
>>>
>>> class DSCPAF4
>>>
>>> set ipv4 dscp af41
>>>
>>> Bandwidth percent 17
>>>
>>> random-detect dscp
>>>
>>> !
>>>
>>> Class DSCPAF3
>>>
>>> set ipv4 dscp af31
>>>
>>> bandwidth percent 25
>>>
>>> random-detect dscp
>>>
>>> !
>>>
>>> Class DSCPAF2
>>>
>>> set ipv4 dscp af21
>>>
>>> bandwidth percent 20
>>>
>>> random-detect dscp
>>>
>>> !
>>>
>>> Class CS6
>>>
>>> bandwidth percent 3
>>>
>>> !
>>>
>>> Class class-default
>>>
>>> Fair-queue
>>>
>>> random-detect
>>>
>>>
>>> As recommended by Cisco Doc for IOS XR , I have enabled priority &
>>> policing
>>> for VOIP/Signaling (EF class), This policer ensures that the priority
>>> traffic does not starve all other traffic on the line card, which
>>> protects
>>> low-priority traffic from starvation.
>>>
>>> All other classes were configured to guarantee min. BW using the
>>> Bandwidth
>>> cmd.
>>>
>>>
>>> So after this, the customer advised that he need no Policing on the
>>> VOIP/Signaling
>>> (EF class), so it can allocate as much BW as possible without policing in
>>> case of conguestion, Put in mind that im working on an IP/MPLS NGN for
>>> mobile operator.!!!!
>>>
>>>
>>>
>>> *So what will happen if i removed the policing from the VOIP class & kept
>>> only the priority cmd:*
>>>
>>> *
>>> *
>>>
>>> *1- Will it be like Dynamic Priority BW alocation for the VOIP class if
>>> there is avalaiable BW & will it starve the BW in case of conguestion ?
>>> *
>>>
>>> *
>>> *
>>>
>>> *2- Will it be like Dynamic Priority BW alocation for the VOIP class if
>>> there is avalaiable BW, but will be stopped in case of conguestion as
>>> there
>>> are minmum BW garntee for other queues based on the cmd bandwidth
>>> percent. *
>>>
>>>
>>>
>>> Appretiate your advise.
>>>
>>> -----------------------------------
>>> Thanks & B.regards
>>> Ahmed Elhoussiny,CCIE# 21988 (R&S)
>>> Network Consultant & Cisco Academy Instructor
>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
>>>
>>> _______________________________________________________________________
>>> Subscription information may be found at:
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>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>
>
> --
> -----------------------------------
> Thanks & B.regards
> Ahmed Elhoussiny,CCIE# 21988 (R&S)
> Network Consultant & Cisco Academy Instructor

Blogs and organic groups at http://www.ccie.net
Received on Tue Apr 28 2009 - 15:54:01 ART