From: Kenneth Wygand (KWygand@customonline.com)
Date: Tue Jul 13 2004 - 15:58:07 GMT-3
--------------------------
Sent from my BlackBerry Wireless Handheld
-----Original Message-----
From: Kenneth Wygand <KWygand@customonline.com>
To: 'ccie2be@nyc.rr.com' <ccie2be@nyc.rr.com>
Sent: Tue Jul 13 14:56:56 2004
Subject: Re: Max-reserved-bandwidth question
Hey Tim,
I copied the group on this email because I'm sure many people have the same concern you do (about what to do if 12.2T is loaded on routers before August 1st wheb 12.2T features will not specifically be tested).
One thing to remember is that this is really a change in implementation, not a 12.2T "feature" per se. Although the difference may seem trivial, the implication is huge.
If you have two ways of doing something (12.2T and pre-12.2T), you will (or should) always have a pre-12.2T way of doing it before August 1.
This, however, is a change in implementation. There is no "legacy" way of configuring something when they change how something works. If they tell you to give something 20% bandwidth, there is only one way of doing it, and that way may differ depending on which side of the 12.2T fence you are on. Its impossible to configure something the "old way" when the programming code has physically changed and will not allow you to do that anymore.
Having that said, I -strongly- doubt they will trick you by giving you requirements for the old way of doing things and expect you to adapt the question into configuration commands for current IOS implementation. Especially since the feature now lends itself more nicely to the way in which the questions can be asked, as follows:
Intuitive way a question could be asked implying new implementation:
"Reserve 20% of the total link bandwidth for ftp"
Un-intuitive way a question would have to be asked, implying old implementation:
"Reserve 20% of the percentage of available bandwidth that can be reserved for ftp"
In other words, we'll all be fine. Everything will be A-OK!
Ken
--------------------------
Sent from my BlackBerry Wireless Handheld
-----Original Message-----
From: ccie2be <ccie2be@nyc.rr.com>
To: Kenneth Wygand <KWygand@customonline.com>
Sent: Tue Jul 13 11:46:36 2004
Subject: Re: Max-reserved-bandwidth question
Hey Ken,
Just wanted to let you know that your explanation is excellent.
I knew they had been a change in the meaning of bandwidth percent from older
verions of ios to newer ones, but never saw an explanation that explained
the change as clearly and succinctly as you just did. Now, for us guys
taking the lab this month, which meaning should we use - the old or new one?
Or, had we better check which version of IOS is running?
My first thought would be that since 12.2T features won't be tested until
August, I should use the old meaning, but, on the other hand,
bandwidth-percent isn't a 12.2T feature and the routers might have 12.2T
running even though the lab won't test on 12.2T specific features.
Hmmm, makes one wonder, doesn't it?
Thank you, Tim
----- Original Message -----
From: "Kenneth Wygand" <KWygand@customonline.com>
To: "Yasser Aly" <yasser.aly@noorgroup.net>; "Scott Savage"
<rolande23@sbcglobal.net>; <ccielab@groupstudy.com>
Sent: Tuesday, July 13, 2004 8:12 AM
Subject: RE: Max-reserved-bandwidth question
> Scott,
>
> While either answer will technically work, "max-reserved-bandwidth 80" is
the more correct answer. This merely sets and upper bound on the cumulative
percentages of bandwidth you can "guarantee" (more appropriate than
"reserve", because other classes can use the bandwidth "guaranteed" for
another class when not being used). In older versions of code (12.1T and
12.2), the percentage you guaranteed through "bandwidth-percent", is
actually a percent of the "max-reserved-bandwidth" as opposed to a
percentage of the full link bandwidth. However, in 12.2T and 12.3, this has
been changed to reflect the percentage of the full link bandwidth.
>
> So in versions 12.2T and 12.3, the max-reserved-bandwidth is not used in
any calculations, rather it is merely an upper boundary. It's like if you
wanted to take $800 out of an ATM machine (banking, not asynchronous
transfer mode ;-). Does it matter if the upper limit is $800 or $1000? No,
either way you will be able to accomplish what you need. But if the default
is $750, it would perhaps appear "more correct" or show a better
understanding of the technology if you raised it to $800, or 80% in your
case.
>
> There is still one catch. This leaves 20% for the default-class, but this
is not guaranteed during times of congestion. If you want to -guarantee-
20% for the default-class, you will need to include a bandwidth-percent
command under the default-class and then change the max-reserved-bandwidth
to 100, since you are now actually reserving (again, I don't like the
terminology) 100% of the bandwidth.
>
> Hope this helps!
> Ken
>
> ________________________________
>
> From: nobody@groupstudy.com on behalf of Yasser Aly
> Sent: Tue 7/13/2004 5:07 AM
> 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
>
> _______________________________________________________________________
> Please help support GroupStudy by purchasing your study materials from:
> http://shop.groupstudy.com
>
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Please help support GroupStudy by purchasing your study materials from:
> http://shop.groupstudy.com
>
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sun Aug 01 2004 - 10:11:54 GMT-3