From: Vijaykrishna (vijaykrishna@xxxxxxxxxxx)
Date: Fri Jun 30 2000 - 18:59:19 GMT-3
About the ex. in 12.1 I think the line may use upto 128K burst for the
100msec and NOT T1 because
by the calculcation--
Tc interval = 0.1sec
Bc = 6400 bits
Be = 6400 bits
CIR = Bc/Tc = 64000
EIR = Be/Tc = 64000
PIR = CIR+EIR = 128K RATE of traffic only for Tc interval
Similarly considering the above calculation for the ex. in 12.0 should be
traffic-shap rate 64000 8000 184000
where 184000 = (1536000/8) - 8000 so this shaping allows link to burst at
T1 rate for the first interval.
but again I don't get how to fit the 30 sec part.
however 46080000=1536000*30 ie. T1 rate * 30 sec.
Can anyone pl explain this better ??
Vijay
-----Original Message-----
From: Sam Li <sxl099@hotmail.com>
To: ccielab@groupstudy.com <ccielab@groupstudy.com>
Date: Friday, June 30, 2000 4:27 PM
Subject: Frame Relay Traffic Shape
>I am puzzled on traffic shaping. I don't have problem on what commands to
>use. I just could not figure out where do you get all parameters used in
the
>command.
>
>I tracked back the archive of the mailing list, i.e. at
>
>http://www.groupstudy.com/archives/ccielab/200005/msg00050.html
>I think the parameters posted at fatkid.com
>("traffic-shape group 101 16000 32000 32000 1000")
>are ok to serve the purpose although it is confusing because of the same
>number as 32kbps and not good because of using two second as the interval.
>
>
>I would use
>traffic-shape group 101 16000 2000 2000 which is 1/8 second as the
interval.
>
>In the same email mentioned the some helpful info on CCO, what is the url?
>
>I check on the cisco manuals for better answer. Here is what I find.
>
>
>*****************12.0 manual *************************
>at
>http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/qos_
c/qcpart4/qcgts.pdf
>
>QC-101 to 102
>
>It states
>
>Constrained Access Rate Example
>In this example, a customer may use all of a T1 line for 30 seconds in a
>burst, but the long-term average is limited to 64 kbps. This configuration
>restricts the amount of load the system can induce on the outbound network
>interface.
>
>interface <his interface or sub-interface>
>traffic-shape rate 64000 8000 46080000
>
>
>If you need to restrict the amount of load the system can induce both
>outbound and inbound, and therefore the total load it can induce on the
>Internet Service Provider (ISP), configure traffic shaping on both the
>inbound and outbound interfaces, as in the following example:
>
>interface <serial interface or sub-interface>
>traffic-shape rate 64000 8000 46320000
>interface <LAN interface>
>traffic-shape rate 64000 8000 46320000
>
>
>****************** 12.1 Manual *****************
>
>at
>http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/qos
_c/qcprt4/qcdgts.pdf
>
>page QC-135
>
>Constrained Access Rate Example
>In this example, a T1 line may be used for 100 milliseconds in a burst, but
>the long-term average is limited to 64 kbps. This configuration example
>restricts the amount of load the system can induce on the outbound network
>interface.
>
>interface serial 4/1:0
>traffic-shape rate 64000 6400 6400
>
>
>If you need to restrict the amount of load the system can induce outbound,
>and therefore the total load it can impose on the Internet service provider
>(ISP), configure traffic shaping on the outbound interfaces.
>
>
>**********
>
>I think the parameters used in 12.0 manual were wrong and in 12.1 were
>correct. I think on 12.0 manual it should be
>
>interface <his interface or sub-interface>
>traffic-shape rate 64000 8000 440000 but that has nothing to with "30
>second".
>
>44000=1544000/8-8000
>
>I especially don't understand how do they get the parameters for the ISP
>example in 12.0 manual showed above.
>
>Maybe that is why they don't use that example in 12.1 manual any more.
>
>Could someone explain what do I miss?
>
>If the lab ask you to "a customer may use all of a T1 line for 30 seconds
in
>a burst, but the long-term average is limited to 64 kbps"
>
>What interval you are going to use? how does the "30 seconds" get into the
>calculation?
>
>How sorry it will be if you know all commands but can't figure out the
>numbers to fill in!
>
>
>
>Thanks in advanced,
>
>
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