From: Devi Mallampalli (Devi.Mallampalli@chubb.com.au)
Date: Tue Jul 13 2004 - 09:39:11 GMT-3
Hi Yasser,
Firstly , it depends upon whether you are using VIP based distributed
platforms like 7507 or non VIP based modular platforms like 2600s or
3600s because non VIP platforms use this feature predominantly to adjust
the amount of B/W that must be left over.
From my limited understanding , this feature can be useful to deploy
with in CBWFW with "bandwidth" command or LLQ with "priority" command
among various queuing mechanisms and the way she kicks in is purely
dependent upon the "policy-maps or service policy you are configuring.
The fact that CBWFQ/LLQ can offer much more granularity and control,
this feature is useful when compared to PQ or CQ which I think from
memory will use 100% of the available interface B/W by default.
Now to answer to your question whether to use 80% or 100%, I would not
go for 100% simply because I would like to leave 20% of the B/W for
other important kinds of traffic such as Routing protocol updates and
keep alives , just like the way you would not want to manipulate IP
precedence values of 6 & 7 which will be used by system updates.
Second reason why I would not use 100% because the fact that CBWFQ or
LLQ are there primarily to protect the Latency sensitive traffic such as
RTP & RTCP (or any important corporate ERP apps) which is traveling over
a "burstable " medium , we got to take care about other non easily
measurable traffic too such as Emails & HTTP for example. And these guys
can use the remaining 20% of the available B/W if required.
But another important point to note here is , it also depends upon what
kind of IOS code your are running because that can influence how these
(available B/W , interface B/W & Bandwidth percent command ..etc)
features are calculated. For example, with 12.2 T & 12.3 main line
codes, the "bandwidth percent" command is NOT any more referring to
"Available B/W" ( which is equals to max reserved B/W * interface B/W -
sum of priority classes which you configure with in LLQ config) . But
instead these newer versions will be making "bandwidth percent" command
to use the "Interface B/W" instead. And older codes work in the opposite
way.
Hope this helps.
Devi..
-----Original Message-----
From: Yasser Aly [mailto:yasser.aly@noorgroup.net]
Sent: Tuesday, 13 July 2004 7:07 PM
To: Scott Savage; ccielab@groupstudy.com
Subject: RE: Max-reserved-bandwidth question
Hi Scott,
I didn's said that this is an RSVP question. It is as you said a CBWFQ
question. Still didn't get an answer on whether to set the
max-reserved-bandwidth to be 80 or 100.
Regards,
Yasser
-----Original Message-----
From: Scott Savage [mailto:rolande23@sbcglobal.net]
Sent: Tue 7/13/2004 6:10 AM
To: Yasser Aly; ccielab@groupstudy.com
Cc:
Subject: Re: Max-reserved-bandwidth question
Yasser are you sure this is an RSVP question? Sounds
like you need to be using CBWFQ and setting classes
with bandwidth percent statements or using Custom
Queuing.
--- Yasser Aly <yasser.aly@noorgroup.net> wrote:
> Hi Group,
>
> The task is asking to do the following
>
> Assign 30% for Class A
> Assign 20% for Class B
> Assign 30% for Class C
>
> The rest of the traffic will use the default-class.
>
> As the summation of the reserved bandwidth is over
> 75% so the
> max-reserved-bandwidth needs to be modified.
>
> My question is that would the max-reserved-bandwidth
> changed to be 80%,
> or will it be changed to be 100% ?
=====
-- Scott Savage
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