From: Kumar Raja-Q16843 (Raja.Kumar@motorola.com)
Date: Wed Nov 16 2005 - 03:04:23 GMT-3
Thanks Daniel for your inputs, let me rephrase the question, just want
to be doubly sure, this was a wicked question thrown at us during the
practice, but then it make sense......this question makes me remember
the response of Tim in the mail train "Top Reasons People Fail the Lab",
Coming to the point...
CIR = 10 Mbps; Normal Burst = 500 kbps; Maximum Burst = 1 Mbps
rate-limit input <Cir_ Bits/sec> <Normal Burst Bytes> <Maximum Burst
Bytes> transmit exceed-action drop
The attribute CIR is straight forwards since it is in bits/sec, the
given value is the same measure
My test is here with the Normal Burst, the attribute in the command has
a measure of bytes, let me try (pardon me if I am being stupid)
(500*1000/8)*1.5 = 93750 bytes
Same the case with Maximum burst, the value would be (1000000/8)*1.5 =
187,500 bytes
Then the command would be
rate-limit input 10000000 93750 187500 transmit exceed-action drop
Has my way calculating the values are correct or am I missing something
here?
I guess, , Does it still sound stupid?
Thanks in advance,
Raja
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Daniel Berlinski
Sent: Wednesday, November 16, 2005 9:49 AM
To: Kumar Raja-Q16843; ccielab@groupstudy.com
Subject: RE: Question on Qos rate-limiting
Kumar
IMHO your numbers make a Tc of 50ms (bc/cir *1000) hence you area
leaking bytes into the line across 20 intervals in one sec to send 10Meg
If you allow a burst of 125000 bytes, it means that after 20 intervals
of 50ms each you will end up sending 125000 bytes(1Mbps) * 20= 20Mbps
To allow a max burst of 1Mbps I think (I could be wrong please someone
correct me in this one) you should use a be of 6250 bytes
Cheers
________________________________
From: nobody@groupstudy.com on behalf of Kumar Raja-Q16843
Sent: Wed 16/11/2005 7:11 a.m.
To: ccielab@groupstudy.com
Subject: Question on Qos rate-limiting
Hi Guys,
In rate-limiting , I have this question, a CIR of 10 Mbps with a normal
burst of 500 kbps and a maximum burst of 1 Mbps, the traffic should pass
if the set condition matches if not the packet be dropped.
Interface Ethernet0/0
ip address 10.10.10.1 255.255.255.0
rate-limit input 10000000 62500 125000 conform-action transmit
exceed-action drop
Kindly advice if my configuration is correct, the above solution is
because I was given the normal burst value of 500 kbps, but actually we
don't need this value, if we are given with the CIR and the normal burst
can be calculated as (CIR*1.5/8), when the value of normal burst is
explicitly given, should we use or we still go ahead and calculate the
normal using the formula.
Thanks in advance,
Raja
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