From: steven.j.nelson@xxxxxx
Date: Mon Aug 26 2002 - 12:02:47 GMT-3
Jim
The config you have supplied below should give an average transmisson rate
of 320000 bits per sec, My calculations are based on the following
TC = 0.125
BC = 8000 (bits per time slot (.125 Seconds)
BE = 32000 (Excess bits per time slot (.125 Seconds), providing
bucket tokens are available)
So...
8000 + 32000 = 40000 bits per time slot (0.125 Seconds)
1 Second = 8 time slots (0.125 * 8 = 1 Second)
So 40000 * 8 = 320000 bits per second
320000 / 1024 to get Kilo Bytes = 312.5K per second
Surley this is not correct ?
I would have thought with a CIR of 64K you would need :-
TC = 0.125
BC = 6000 (bits per time slot (.125 Seconds)
BE = 2000 (Excess bits per time slot (.125 Seconds), providing
bucket tokens are available)
So...
6000 + 2000 = 8000 bits per time slot (0.125 Seconds)
1 Second = 8 time slots (0.125 * 8 = 1 Second)
So 80000 * 8 = 64000 bits per second
64000 / 1024 to get Kilo Bytes = 62.5K per second
I may be completley wrong here but I think the trick is that the values are
given in bits and the timeslot is BC, which ate 0.125 means that you need 8
to get bits per sec which you can translate to the CIR which is shown as
64K, but this is in seconds.
HTH, probably not!!
Thanks
Steve
-----Original Message-----
From: Jim Brown [mailto:Jim.Brown@caselogic.com]
Sent: 26 August 2002 15:24
To: 'kpalmer'
Cc: 'ccielab@groupstudy.com'
Subject: RE: I need FRTS help or review
After your e-mails I rethought my stance on FRTS. I did a little more
research and I believe my original configuration at the bottom of the post
is the correct answer from a lab or testing context for a 96Kbps port and
64Kbs contracted CIR.
map-class frame-relay TestShape
frame-relay cir 64000
frame-relay be 32000
frame-relay bc 8000
I'm basing this on a single new piece of information I turned-up. Check the
Networkers 2002 CCIE Power Session, in their FRTS example, they configure
the parameters exactly as I have described below.
I still stand by my original assessment of Cisco's CIR set to the providers
CIR and Cisco's BE set to the difference between providers CIR and port
speed.
I'm posting this back to the list to hopefully open up discussion again.
-----Original Message-----
From: kpalmer [mailto:kip.palmer@verizon.net]
Sent: Sunday, August 25, 2002 8:27 PM
To: 'Jim Brown'
Subject: RE: I need FRTS help or review
Line speed | Access Rate | Port Speed
=======================================
What you bought from the Provider. Per DLCI.
Average Rate | configured CIR (not mincir)
=======================================
When Shaping 128 to 64, it's 64k, with Bc ='s the Average Rate of remote
64, /8.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jim Brown
Sent: Sunday, August 25, 2002 1:04 PM
To: ccielab@groupstudy.com
Subject: I need FRTS help or review
Everything I have read about FRTS doesn't seem to clear up the use of
BE, BC, CIR, and MINCIR. I have been unable to locate a solid resource
explaining the concept with any finality.
I've read most of the relevant Usenet postings on Deja, watched the
threads on groupstudy, scoured CCO, and examined the QOS v1.0 course
material.
I will throw out my assumptions and let list members either verify or
shoot holes on my take of FRTS.
A few definitions up front:
AR is the Access Rate or Port Speed of the connection to the frame relay
cloud. This is the maximum number of bits that can be transmitted to the
cloud.
CIR is the Committed Information Rate. This is the maximum number of
bits the provider promises to transmit. Anything above the CIR and below
the access rate will have the DE bit marked and is eligible for
discard/drop during times of congestion.
Lets take a hypothetical circuit for instance, a port speed of 96Kbps
and a CIR of 64Kbps.
The way I read the documentation, in a Cisco configuration CIR should be
set to the actual provider CIR or 64000. The BE or burst excess should
be set to the difference between the access rate and the CIR. I think BE
should be set to 32000, the difference between 96 and 64.
Here is a brief sample config:
map-class frame-relay TestShape
frame-relay cir 64000
frame-relay be 32000
The map-class could then be applied to the frame map or the interface. I
was previously under the impression you would set the Cisco CIR to the
port speed and the minCIR to the provider contracted CIR. I don't think
this is really the case?
Here is an example:
map-class frame-relay TestShape
frame-relay cir 96000
frame-relay mincir 64000
Comments or suggestions? Is this wrong, why or why not?
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