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timaz
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traffic shaping

Sat Apr 21, 2012 7:58 am

Hi all; I'm confused !

with this command, what are the values of Bc and Be?

interface fast 0/0
traffic-shape group 101 500000
timaz

Perlhack
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Re: traffic shaping

Sat Apr 21, 2012 8:35 am

Value of Bc can be found by knowing the Tc, but not Be ... thats extra.
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timaz
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Re: traffic shaping

Sat Apr 21, 2012 8:49 am

Perlhack wrote:Value of Bc can be found by knowing the Tc, but not Be ... thats extra.



so what are the values of Bc and Bc with just the mentioned command?!!
timaz

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Re: traffic shaping

Sat Apr 21, 2012 9:06 am

Why not do a show traffic-shape and see for yourself?

timaz
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Re: traffic shaping

Sat Apr 21, 2012 9:45 am

mellowd wrote:Why not do a show traffic-shape and see for yourself?


I take this command from "CCIE RS cert guide". actually this command has output that shows the Bc and Be values. but I cannot calculate the same values. in this book, the author said "if we don't determine the Bc and Be values, it will be 0ne-quarter of the shaping rate". but with regards to this formula, {Tc=Bc/shapingRate}, the values must be different than what is shawn in the output. so if you see this command, can you calculate Bc and Be? .. what is those values?
timaz

timaz
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Re: traffic shaping

Sat Apr 21, 2012 10:31 am

I think the famous formula {Tc=Bc/shapingRate} don't apply on GTS. am I right?
timaz

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Re: traffic shaping

Sat Apr 21, 2012 2:39 pm

IOS will apply a default Tc value for the shaper. I do not recall what the default value really is but if its 25ms for a 50M shaper:

Tc = 25 ms | Tc in a sec = 40 | Bc = 1250000 bits

Max Be value can not be determined without knowing the line rate of the circuit.
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timaz
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Re: traffic shaping

Sat Apr 21, 2012 2:56 pm

the output being shown in this book has these values:

Bc=12000 bits
Be=12000 bits
Tc=24 ms

these values are true with the formula, but I don't know how these are calculated? does anyone know?
timaz

timaz
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Re: traffic shaping

Sun Apr 22, 2012 7:47 am

nobody knows?
timaz

d_estin_y
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Re: traffic shaping

Tue Apr 24, 2012 4:05 am

timaz wrote:the output being shown in this book has these values:

Bc=12000 bits
Be=12000 bits
Tc=24 ms

these values are true with the formula, but I don't know how these are calculated? does anyone know?

I do not get how the Tc is calculated.

but with the given Tc of 24ms, the calculation of Bc is

500000 * 24 / 1000

which means you could send 12000 bits each 24ms

timaz
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Re: traffic shaping

Tue Apr 24, 2012 5:54 am

d_estin_y wrote:
timaz wrote:the output being shown in this book has these values:

Bc=12000 bits
Be=12000 bits
Tc=24 ms

these values are true with the formula, but I don't know how these are calculated? does anyone know?

I do not get how the Tc is calculated.

but with the given Tc of 24ms, the calculation of Bc is

500000 * 24 / 1000

which means you could send 12000 bits each 24ms



yes, that's true. the calculated values are true with this formula. but I don't understand how they are calculated with regards to the command. i think there must be default values. but what they are?
timaz

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Re: traffic shaping

Tue Apr 24, 2012 7:45 am

Code: Select all
C1811#show traffic-shape

Interface   Vl1
       Access Target    Byte   Sustain   Excess    Interval  Increment Adapt
VC     List   Rate      Limit  bits/int  bits/int  (ms)      (bytes)   Active
-             100000000 625000 2500000   2500000   25        312500    -   
C1811#
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