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RE: CBWFQ Percentage Calculation Doubt posted 11/01/2004
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Interesting that you are having this problem.  When you do a "show
interface" command, do you see an entry for "available bandwidth"?  That is
supposed to be an indicator of 75% of your absolute bandwidth.

The error you are seeing is indicative that it's using absolute, which is
odd.  Not supposed to be doing that according to their docs.   Although in
doing some research, it appears they are changing the concepts again moving
into 12.3 (so 12.2T stuff).

There is a bandwidth-percent and bandwidth-remaining-percent command now!
Go figure.  Check out:
http://www.cisco.com/en/US/tech/tk543/tk757/technologies_tech_note09186a0080
103eae.shtml

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guid
e09186a0080087af0.html

You gotta love the IOS programmers sometimes.  ;)

Scott 

-----Original Message-----
From: Swaroop Potdar [mailto:swarooppotdar@xxxxxxxxxxx] 
Sent: Monday, November 01, 2004 9:33 AM
To: swm@xxxxxxxxxx
Cc: ccielab@xxxxxxxxxxxxxx
Subject: RE: CBWFQ Percentage Calculation Doubt

Hi Scott,

As you pointed out in the first config, if done in 12.2 it will reserve 75%
of the line bandwidth when i tried it still thinks that these total 100% is
absolute and not relative ie( 75% of line bandwdith)

as it gives me a message saying requested 34% bandwidth available only 9%
bandiwdth.

is this the change in 12.2 and 12.2T ???

I am running 12.2.(14)T enterprise plus on 2600

Warm Regards,
Swaroop

>From: "Scott Morris" <swm@xxxxxxxxxx>
>Reply-To: <swm@xxxxxxxxxx>
>To: "'Swaroop Potdar'" 
><swarooppotdar@xxxxxxxxxxx>,<ccielab@xxxxxxxxxxxxxx>
>Subject: RE: CBWFQ Percentage Calculation Doubt
>Date: Mon, 1 Nov 2004 08:42:58 -0500
>
>Looking at your first policy:
>policy-map CBWFQ
>   class queue1
>    bandwidth percent 22
>   class queue2
>    bandwidth percent 7
>   class queue3
>    bandwidth percent 37
>   class queue4
>    bandwidth percent 34
>
>Those values add up to 100.  In 12.2, that will reserve 100% of the 
>AVAILABLE bandwidth (75% of line bandwidth).  So if you had a 1 Mb 
>line, that would reserve 100% of 750K.  There still would be 25% 
>leftover for 'unclassified traffic' which is automatically considered 
>to be class-default.
>
>In your second policy:
>policy-map CBWFQ
>   class queue1
>    bandwidth percent 22
>   class queue2
>    bandwidth percent 7
>   class queue3
>    bandwidth percent 37
>   class queue4
>    bandwidth percent 22
>   class class-default
>    bandwidth percent 12
>
>You actually specify the class-default configuration.  This is 
>acceptable, but bear in mind that without the setting your 
>max-reserved-bandwidth to 100% on the interface, you aren't accomplishing
as much as you would think!
>You're giving a guarantee, but a pseudo-limit in weighted round robin 
>scheduling by giving a number to the class-default while not changing 
>other default behaviors.
>
>As far as which one is correct, that will entirely depend on how your 
>lab is worded!  If you are told to give certain guarantees to otherwise 
>unclassified traffic, then you should specify stuff for the class-default.
>If not, leave it alone!  Think through what the router will be 
>doing/thinking and that should help answer the question!
>
>HTH,
>
>Scott
>
>-----Original Message-----
>From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf Of 
>Swaroop Potdar
>Sent: Monday, November 01, 2004 8:23 AM
>To: swm@xxxxxxxxxx; ccielab@xxxxxxxxxxxxxx
>Subject: RE: CBWFQ Percentage Calculation Doubt
>
>Hi Scott,
>
>Thanks for your reply....though still have a doubt would appreciate 
>some more of your time
>
>
>I am pasting the config below..is the interface config correct i mean 
>can we
>
>do reserved bandwidth 100% and if we do so do we have to consider some 
>space
>
>for the default class....and on the same interface i have given two 
>different service policy variations config which one is correct ?
>
>the one without default class or the one with it. as there is a default 
>class by default is it mandatory to use and allocate some percentage or 
>leave aside some percentage for it.
>
>
>--------------------------------------------------------
>
>
>interface Ethernet0/0
>ip address 133.1.23.2 255.255.255.128
>ip nbar protocol-discovery
>ip pim sparse-mode
>max-reserved-bandwidth 100
>service-policy output CBWFQ
>half-duplex
>end
>
>1)
>
>class-map match-all queue1
>   match protocol telnet
>class-map match-all queue3
>   match protocol http
>class-map match-all queue2
>   match protocol ftp
>class-map match-all queue4
>   match protocol dlsw
>!
>!
>policy-map CBWFQ
>   class queue1
>    bandwidth percent 22
>   class queue2
>    bandwidth percent 7
>   class queue3
>    bandwidth percent 37
>   class queue4
>    bandwidth percent 34
>!
>
>or
>
>2)
>
>class-map match-all queue1
>   match protocol telnet
>class-map match-all queue3
>   match protocol http
>class-map match-all queue2
>   match protocol ftp
>class-map match-all queue4
>   match protocol dlsw
>!
>!
>policy-map CBWFQ
>   class queue1
>    bandwidth percent 22
>   class queue2
>    bandwidth percent 7
>   class queue3
>    bandwidth percent 37
>   class queue4
>    bandwidth percent 22
>   class class-default
>    bandwidth percent 12
>!
>
>-----------------------------------------
> >From: "Scott Morris" <swm@xxxxxxxxxx>
> >Reply-To: "Scott Morris" <swm@xxxxxxxxxx>
> >To: "'Swaroop Potdar'" <swarooppotdar@xxxxxxxxxxx>, 
> ><ccielab@xxxxxxxxxxxxxx>
> >Subject: RE: CBWFQ Percentage Calculation Doubt
> >Date: Mon, 1 Nov 2004 08:08:47 -0500
> >
> >In 12.1, the percentage was calculated based on interface bandwidth, 
> >allowed to a max additive value of 75%.
> >
> >In 12.2, this was changed to calculate based on "available 
> >bandwidth", which was a pre-calculated value of 75% of the line 
> >bandwidth.  So you could reserve 100% of this amount.
> >
> >HTH,
> >
> >
> >Scott Morris, MCSE, CCDP, CCIE4 (R&S/ISP-Dial/Security/Service 
> >Provider) #4713, JNCIP, CCNA-WAN Switching, CCSP, Cable 
> >Communications Specialist,
>IP
> >Telephony Support Specialist, IP Telephony Design Specialist, CISSP 
> >CCSI #21903 swm@xxxxxxxxxx
> >
> >
> >
> >
> >-----Original Message-----
> >From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf 
> >Of Swaroop Potdar
> >Sent: Monday, November 01, 2004 6:16 AM
> >To: ccielab@xxxxxxxxxxxxxx
> >Subject: CBWFQ Percentage Calculation Doubt
> >
> >Hi Group,
> >
> >I wanted to confirm this doubt about CBWFQ,
> >
> >-----------------
> >
> >If in a question the default queue size to be used is not given
> >
> >then;
> >
> >do we have to do the bandwidth calculation without factoring the 
> >max-reserved-bandwidth.
> >
> >and if the default queue size for the traffic is given
> >
> >then
> >
> >we have to do the bandwidth percentage calculation as 100% of the
>interface
> >bandwidth
> >
> >?????
> >
> >
> >
> >Regards,
> >Swaroop
> >------------------------------------------------------------------
> >Life Is Short & Sweet.
> >Live It To The Fullest.
> >------------------------------------------------------------------
> >
> >_________________________________________________________________
> >Yantras for power and success. Yantras for peace and joy.
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> >change your life.
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>
>Regards,
>Swaroop.
>------------------------------------------------------------------
>Life Is Short & Sweet.
>Live It To The Fullest.
>------------------------------------------------------------------
>
>_________________________________________________________________
>Yantras for power and success. Yantras for peace and joy.
>http://www.astroyogi.com/NewMsn/astroshopping/yantra/ Yantras that 
>change your life.
>
>_______________________________________________________________________
>Subscription information may be found at:
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>


Regards,
Swaroop.
------------------------------------------------------------------
Life Is Short & Sweet.
Live It To The Fullest.
------------------------------------------------------------------

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