From: Bauer, Rick (BAUERR@xxxxxxxxxxx)
Date: Wed Aug 28 2002 - 15:55:29 GMT-3
This should help. The first couple of lines will answer your question in
regard to CIR, BE, BC.
http://www.cisco.com/warp/customer/125/21.shtml
Rick, #9482
-----Original Message-----
From: Volkov, Dmitry (Toronto - BCE) [mailto:dmitry_volkov@ca.ml.com]
Sent: Wednesday, August 28, 2002 2:07 PM
To: 'Jim Brown'; 'Colin Barber'; 'Omer Ansari'
Cc: 'ccielab@groupstudy.com'
Subject: RE: I need FRTS help or review
Jim,
You are right traffic will be delayed and sent within 9th Tc interval
(assuming Tc=1/8 sec).
But Be is still Be - it is number of bits, and Be+Bc =< Port Speed
(clocking) * Tc.
We have to put actual number in config.
40000 bits will not be transmitted during 1st Tc - only 12000 bits.
Other bits will be delayed until 9th Tc.
Be - number of bits will be transmitted within 1st Tc ==> be = 12000
-8000(Bc) = 4000 bits
and this number 4000 we have to put in config as Be. The other bits will be
delayed / dropped, whatever.
I'm not 100% sure about it, but I got this logic from CCO.
Colin right - the documentation on this subj is very unclear.
This subj is like religion for me - believe or not believe :)
Dmitry
> -----Original Message-----
> From: Jim Brown [mailto:Jim.Brown@caselogic.com]
> Sent: Wednesday, August 28, 2002 11:35 AM
> To: 'Colin Barber'; 'Omer Ansari'; 'ccielab@groupstudy.com'
> Subject: RE: I need FRTS help or review
>
>
> You do not necessarily need 320Kps available during the first
> interval. The
> packets are software queued before they are placed onto the
> TxRing. This is
> the whole idea behind shaping.
>
> They are not placed on the wire at exactly the same speed
> designated per TC
> interval.
>
> List, if I'm way off base please correct me and help me see the light.
>
> -----Original Message-----
> From: Colin Barber [mailto:Colin.Barber@telewest.co.uk]
> Sent: Wednesday, August 28, 2002 9:09 AM
> To: 'Omer Ansari'; 'ccielab@groupstudy.com'
> Subject: RE: I need FRTS help or review
>
>
> What's the access speed of the interface? If it's 96k then this is
> incorrect. In the first time slot BC+BE=40000. For that
> amount of data to be
> transferred in the first timeslot the access speed will need to be
> 40000*8=320kbps.
>
> Colin
> -----Original Message-----
> From: Omer Ansari [mailto:omer@ansari.com]
> Sent: 28 August 2002 10:56
> To: ccielab@groupstudy.com
> Cc: steven.j.nelson@bt.com; Jim.Brown@caselogic.com;
> kip.palmer@verizon.net
> Subject: RE: I need FRTS help or review
>
>
> Guys,
>
> so bottom line is Jim and Steve have correctly done this right?
> It seems good to me, and I too want to stick this once and for all.
>
> omer
>
> On Mon, 26 Aug 2002 steven.j.nelson@bt.com wrote:
>
> > All
> >
> > Jim is correct in this one, his figures pan out as follows
> >
> > CIR 96000
> > MINCIR 64000
> > BE 32000
> > BC 8000
> > TC 0.125Ms
> >
> > So in 8 time slots (1 Second) he will transmit :-
> >
> > 0.125Ms 40000 (BC+BE)
> > 0.125Ms 8000 (BC)
> > 0.125Ms 8000 (BC)
> > 0.125Ms 8000 (BC)
> > 0.125Ms 8000 (BC)
> > 0.125Ms 8000 (BC)
> > 0.125Ms 8000 (BC)
> > 0.125Ms 8000 (BC)
> >
> > Which is equivalent to 96K per second.
> >
> > And when no tokens are available then the MIN CIR will be
> met by the 8000
> BC
> > * 8 = 64000
> >
> > Thanks to Jim for this one.
> >
> > 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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