From: kumara.shunmugam@wipro.com
Date: Thu Aug 11 2005 - 05:44:21 GMT-3
I think he require more clarify with his own example .. the "Peak" rate is always Bc+be. As per his example,his AR is 1.544Mb and the CIR is 512K.His circuit should able to burst up to the interface speed when credits are available..
Tc=125ms (default), which is 1/8 of 1 Sec (1 sec 1000ms)
AR(Access Rate) = 1544K
CIR=512K
Bc = CIR*TC/1000 = 64000 Bits per interval to achieve 512K.(64000*8)=512000
Be = AR-CIR*Tc/1000 =129000, which is 129000*8 = 1032000 per Sec
Peak Rate in one sec will be = Bc*8+be*8 = 512000+1032000 =1544000 =1544Kb
I think this should be the logic.. Correct me if am wrong..
Shun
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Chris Lewis (chrlewis)
Sent: Thursday, August 11, 2005 12:27 AM
To: marvin greenlee; Edwards, Andrew M; ccielab@groupstudy.com
Subject: RE: FRTS Question [bcc][faked-from][bayes]
That sounds about right.
Perhaps the idea of Bc=Be for shaping is getting crossed with that
practice for configuring CAR where that configuration menas no burst?
Andrew, all I can do is confirm my description of shape average and
shape peak and confirm that frame relay shaping operates like shape
average comes directly from the people coding IOS.
Chris
-----Original Message-----
From: marvin greenlee [mailto:marvin@ccbootcamp.com]
Sent: Wednesday, August 10, 2005 8:29 PM
To: 'Edwards, Andrew M'; Chris Lewis (chrlewis); ccielab@groupstudy.com
Subject: RE: FRTS Question [bcc][faked-from][bayes]
Not quite. With a line rate of 1.544 and a time interval of 1/8, you
only have 192k that can be sent during the time period. If you
configure 64k for Bc, then Be can use the other 128k, but not more.
Marvin Greenlee, CCIE#12237, CCSI# 30483 Network Learning Inc
marvin@ccbootcamp.com www.ccbootcamp.com (Cisco Training)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Edwards, Andrew M
Sent: Wednesday, August 10, 2005 6:11 PM
To: Chris Lewis (chrlewis); ccielab@groupstudy.com
Subject: RE: FRTS Question [bcc][faked-from][bayes]
Importance: Low
Hmm..
I'll test the water cause I've had a similar question and discussion
with Marvin...
With the idea in mind that Be is only valid on the first time interval
for the second, if I have a 1.544mbps clocked circuit with a CIR of
512Kbps that I want to always utilize and my provider will allow me to
burst up to the full rate (1.544mbps), I should (generally speaking) set
FRTS as follows:
Frame CIR 512000
Frame mincir 512000
Frame Bc 64000
Frame Be = 512000
No frame adaptive-shape becn
This way I always get 512kbps CIR but can crank up to full line rate in
the first interval???
I thought shaping Be was bits per interval such that each interval I set
a maximum burst for that specific interval... Thus, Bc = Be to hit a
peak rate of 1.544Mbps?
andy
-----Original Message-----
From: Chris Lewis (chrlewis) [mailto:chrlewis@cisco.com]
Sent: Wednesday, August 10, 2005 3:55 PM
To: CCIE CCIE; ccielab@groupstudy.com
Subject: RE: FRTS Question
The simple answer is when that is the behavior you want :)
It is interesting though to look at what that actually does though.
Starting off looking at generic shaping configured with MQC.
Shape average has a burst setup that allows the Be amount of bits to be
sent in addition to the Bc amount of bits on the first interval of a
second.
Shape peak allows Be amount of bits to be sent along with Bc amount of
bits at every time interval.
Frame shaping behaves like the shape average, in that Be is only sent on
the first interval.
So really if you want to have an additional burst of say 1000 bits per
second, configure FRTS with a Be of 1000, as this will allow the shaper
to send an additional 1000 bits once per second on the first time
interval.
I have seen solutions to questions that have Be = Bc for FRTS when the
requirement is to have the burst rate equal to the committed rate, but
that I believe is incorrect. As Be is only added on the first time
interval and not on every time interval, that would not work.
Chris
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
CCIE CCIE
Sent: Wednesday, August 10, 2005 5:29 PM
To: ccielab@groupstudy.com
Subject: FRTS Question
If i configure FRTS when can i put Bc=Be?
Regards,
Patrick
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