Re: Re[7]: QOS CBWFQ to Custom Queuing (again)

From: Hossam (sam6626@yahoo.com)
Date: Mon Jul 21 2003 - 06:39:27 GMT-3


Hi Group,

I know this has been discussed so many times. Only one of them was really fruitful. But even in this fruitful discussion I didnt find a real convincing reason that we need to use the (75%) factor in these calculations.

 Sorry for not recalling names. But someone said that another one convinced him that the 75% is a must in a private discussion. But unfortunately we didnt get this private discussion.

 With all respect and understanding, I still dont find the logic behind using this multiplier. Here is the way I see it.

 Max. Reservable Bandwidth Definition:

  * The max. Available BW on any interface to be reserved for LLQ, RTP and RSVP.

  * Cisco recommends that we do't change the default (75%) to keep at least the rest 25% to the system traffic and other non priority traffic.

 From this understanding I think that this value never kicks in unless someone tries to reserve BW that is more than the 75% (Reserve means LLQ, Priority RTP, RSVp...etc). The 75% will prevent the configuration from exceeding this limit.

 Otherwise the 75% is not in the image at all. It never enters the BW calculations or scheduling traffic.

 In our CQ case we dont have any priority queues unless we have (queue zero). I really dont see the 75% in the image at all.

 I know that I may be mistaken. But can anyone send me the above mentioned private discussion or just give me his understanding.

 Thanks

Hossam

 

badger <badger@pongo.org> wrote:
Hello Jonathan,

Sunday, July 20, 2003, 6:09:44 PM, you wrote:

JVH> I'm guessing the conversion factor is 8 bits/Byte:

JVH> 27 KiloBytes x 8 bits/Byte = 216 Kilobits

JVH> -----Original Message-----
JVH> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
JVH> badger
JVH> Sent: Sunday, July 20, 2003 3:07 PM
JVH> To: Connie Nie
JVH> Cc: Richard Boover; Jim Phillipo; ccielab@groupstudy.com;
JVH> 'brian@cyscoexpert.com'; 'Peter'
JVH> Subject: Re[4]: QOS CBWFQ to Custom Queuing (again)

JVH> Hello Connie,

JVH> Sunday, July 20, 2003, 7:50:12 AM, you wrote:

CN>> There was a thread about this before. One opinion is that the CBWFQ
CN>> bandwidth should (in telnet's example): 14.8%x256x75% ---because the
JVH> total
CN>> reservable bandwidth by default in CBWFQ is 75% of the bandwidth.

CN>> Connie

JVH> Still confused, 75% of the original 256k is 192K. So my question
JVH> still stands, where did the "8" come from ?

JVH> Sometimes I need pictures to help explain 8-)

CN>> Jim,

CN>> How did you get the "8" in your:

CN>> "convert Custom Queuing (KB) to CBWFQ (Kbps): 27KB x 8 = 216Kbps"

Thanks, now it makes sense...as usual, I didn't look at it long enough
to actually read it 8-( I may never pass the lab with these habits!

-- 
Best regards,
badger mailto:badger@pongo.org


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