Let me digest it first before remembering.

  1.  If we are bluntly asked to drop traffic when it exceeds a certain value 
we have to look for some clues or hints in the question that would prompt us to 
use rate-limiting under the interface
  2.  If this task didn't explicitly mention don't use MQC then we could easily 
go for "policing" scenario ?
  3.  If we are given a certain value that we take as CIR that is technically 
sufficient enough to complete the rate-limiting configuration by making Cisco 
recommended formulas for QoS and rate-limiting. It was just a coincidence that 
the task gave the same values that I would calculate in bytes.

Eugene

From: Kingsley Charles 
<[email protected]<mailto:[email protected]>>
Date: Fri, 13 Apr 2012 10:24:40 +0530
To: Eugene Pefti <[email protected]<mailto:[email protected]>>
Cc: 
"[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Subject: Re: [OSL | CCIE_Security] CAR rate-limiting

For QoS policing,

Bc = CIR/8 x 0.25

If Be is not mentioned, Be=Bc


With rate-limiting,

Bc=CIR/8 x 1.5

Be = 2Bc

Remember these always.

Apply it and you will get the answer.


With regards
Kings

On Fri, Apr 13, 2012 at 8:27 AM, Eugene Pefti 
<[email protected]<mailto:[email protected]>> wrote:
Guys,
Am I absolutely insane or INE WB again presented me with a typo?
The tasks says:


-Configure R2 to drop traffic received in its link to VLAN 23 in excess of 
256Kbps.

-Use a committed burst of 384Kb and an excess burst of 768Kb.

-Do not use MQC syntax to accomplish this.

And then the solution gives some out-of-the-place numbers, see the numbers for 
normal burst rate and maximum burst rate. I understand that there are some 
calculations for Be and Bc values but I believe the task clearly mentions those 
burst rates:


interface FastEthernet 0/0

 rate-limit input 256000 48000 96000 conform-action transmit exceed-action drop


Eugene

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