From: Connie Nie (CNie@EPLUS.com)
Date: Sun Jul 20 2003 - 11:50:12 GMT-3
There was a thread about this before. One opinion is that the CBWFQ
bandwidth should (in telnet's example): 14.8%x256x75% ---because the total
reservable bandwidth by default in CBWFQ is 75% of the bandwidth.
Connie
-----Original Message-----
From: badger [mailto:badger@pongo.org]
Sent: Sunday, July 20, 2003 9:33 AM
To: Richard Boover
Cc: Jim Phillipo; ccielab@groupstudy.com; 'brian@cyscoexpert.com'; 'Peter'
Subject: Re[2]: QOS CBWFQ to Custom Queuing (again)
Hello Richard,
Saturday, July 19, 2003, 7:32:29 PM, you wrote:
RB> Jim,
RB> I'm not sure which lab this question comes from, but it seems they are
RB> converting Customer Queuing to CBWFQ. When configuring CBWFQ, I believe
RB> you can use either one (bandwidth or percent) and they give you the same
RB> result. Priority is a little different in since that it will be always
be
RB> service first over CBWFQ (Priority + CBWFQ = LLQ). Note: Custom Queuing
RB> does not support a priority queue, therefore keep this in mind when
RB> converting Custom Queuing to CBWFQ.
RB> This is how they came up with the numbers below (using the Telnet
example):
RB> 1) Custom Queuing - The total byte count for all traffic is 27k Bytes
and
RB> Telnet is allowed 4k bytes. Now lets convert this to a percentage (4/27
=
RB> 14.8%). Therefore, Telnet gets 14.8 percent of the total BW.
RB> 2) When they converted Custom Queuing to CBWFQ, they elected to do it in
BW
RB> (Kbps) instead of percentage (which would have been a lot easier). Lets
RB> convert Custom Queuing (KB) to CBWFQ (Kbps): 27KB x 8 = 216Kbps. Now
lets
RB> multiply the Telnet traffic percentage by the total BW = 14.8% x 216,000
=
RB> 31,968 bps (Notice this value is off from the answer 38Kbps). The
problem
RB> is the Custom Queuing total traffic did not add up to the speed of the
RB> 256kbps interface (this is okay because it is all about percentages).
They
RB> derived their answer from 256,000 x 14.8% = 38kbps. Note: neither one
of
RB> these answer are wrong, the bottom line is the ratio between the
numbers.
RB> Hope this helps.
RB> Rick
RB> At 03:16 PM 7/19/2003 -0400, Jim Phillipo wrote:
>>How do you know whether to use bandwidth or bandwidth percent ?
>>
>>-----Original Message-----
>>From: Jim Phillipo [mailto:jim.phillipo@guardent.com]
>>Sent: Saturday, July 19, 2003 3:08 PM
>>To: ccielab@groupstudy.com
>>Cc: 'brian@cyscoexpert.com'; 'Peter'
>>Subject: QOS CBWFQ to Custom Queuing (again)
>>
>>
>>I know this has been hashed to death but...... The answer they came
>>up with in the answer configs was confusing so I wanted to throw this out.
>>
>>Here is the Scenario:
>>
>>Assume link speed is 256kbps with the folliwing configuration convert it
to
>>CBWFQ:
>>
>>r8# show queuing interface serial 0
>>interface serial 0 queuing strategy: custom
>>Output queue utilisation(queue/count)
>>0/14 1/0 2/0 3/0 4/0 5/0 6/0 7/0 8/0
>>9//0 10/0 1/0 12/0 13/0 14/0 15/0 16/2
>>
>>r8# show queuing custom
>>Current custom queuing configuration:
>>
>>List Queue Args
>>1 16 default
>>1 1 protocol IP TCP WWW
>>1 2 protocol IP TCP FTP
>>1 3 protocol IP TCP Domain
>>1 4 protocol DLSW
>>1 5 protocol IP TCP Telnet
>>1 6 protocol IP TCP SMTP
>>1 1 byte-count 3000 limit 100
>>1 2 byte-count 7000 limit 100
>>1 3 byte-count 1000 limit 100
>>1 4 byte-count 6000 limit 100
>>1 5 byte-count 4000 limit 100
>>1 6 byte-count 4000 limit 100
>>1 16 byte-count 2000 limit 100
>>
>>Here is ther answer:
>>
>>I am at a loss as to how they came up with this, could we have used
priority
>>or bandwidth ?
>>
>>If you have the time could someone quickly go over the difference between
>>bandwith vs priority ?
>>!
>>!
>>!
>>class-map match-all telnet
>> match protocol telnet
>>class-map match-all dlsw
>> match protocol dlsw
>>class-map match-all smtp
>> match protocol smtp
>>class-map match-all ftp
>> match protocol ftp
>>class-map match-all www
>> match protocol http
>>class-map match-all dns
>> match protocol dns
>>!
>>!
>>policy-map cq2cbwfq
>> class dns
>> bandwidth 9
>> queue-limit 100
>> class dlsw
>> bandwidth 57
>> queue-limit 100
>> class telnet
>> bandwidth 38
>> queue-limit 100
>> class smtp
>> bandwidth 38
>> queue-limit 100
>> class www
>> bandwidth 28
>> queue-limit 100
>> class ftp
>> bandwidth 66
>> queue-limit 100
>> class class-default
>> bandwidth 19
>> queue-limit 100
>>!
RB> http://www.groupstudy.com/list/CCIELab.html
Jim,
How did you get the "8" in your:
"convert Custom Queuing (KB) to CBWFQ (Kbps): 27KB x 8 = 216Kbps"
-- Best regards, badger mailto:badger@pongo.org
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