RE: Regarding CAR in QOS

I am not sure what question out of what workbook you are looking at, but I
would just guess that perhaps they did not use the "recommended" value
stated in the DocCD. What vendor / lab are you doing? If it is one of our
labs, I will look into it, if not I would suggest you contact the author of
the lab in question. I have seen it go both ways...usually if it is not
stated, I would use the forumula I gave you...unless for some reason they
give you a specific number to use there.
 

Regards,

Joe Astorino
CCIE #24347 (R&S)
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com <http://www.ipexpert.com/>
  

  _____

From: Raghav Bhargava [mailto:raghavbhargava12_at_gmail.com]
Sent: Monday, June 08, 2009 11:34 PM
To: Joe Astorino
Cc: Cisco certification
Subject: Re: Regarding CAR in QOS

Hi joe,

So lets say in the question it is asked XXX traffic should be transmitted
with an IP Precedence of 4 if its equal to or below 10 mbps.

Now in this CIR = 10 mbps = 10000000 bps

Now as per the formula

Bc = CIR ( in Bps ) /8 * 1.5

Therefore

Bc = 10000000 /8 * 1.5

Bc = 1875000 bps

But the answer is 5000 . So how did 5000 come if I go by the formula.

Please advise??

thanks
raghav

On Mon, Jun 8, 2009 at 8:27 PM, Joe Astorino <jastorino_at_ipexpert.com> wrote:

Hey Raghav,

According to the documentation the recommended values for BC and BE should
be:

Bc: (CIR/8) * 1.5
Be: 2*Be

This can be found here on the DocCD in the QoS command reference under the
rate limit command:
http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_q1.html#wp1015
612
Weather or not you need IPP of 4 is really not relevent to what values you
use for Bc and Be, it is a separate part of the question all together.

Regards,

Joe Astorino
CCIE #24347 (R&S)
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
Raghav Bhargava
Sent: Monday, June 08, 2009 11:18 PM
To: Cisco certification
Subject: Regarding CAR in QOS

Hi Experts,
If the question says XXX traffic should be transmitted with an IP Precedence
of 4 . Now when we configure the CAR , how do we calculate the Normal and
Excessive Burst in this question specifically when IP Precedence is given.

The answer is 5000 each . I just want to know who did we calculated the
Normal and Excessive Burst.

Appreciate all the help.

--
Warm Regards
Raghav
Blogs and organic groups at http://www.ccie.net