From: Brian Dennis (brian@labforge.com)
Date: Thu Apr 17 2003 - 04:10:10 GMT-3
Remember that Cisco's CIR is twice the carrier's CIR. The carrier's CIR
is Cisco's minCIR.
"Carrier CIR is 32K, Local Port Speed is 64K". This translates to:
AR 64000 (aka Port Speed)
CIR 64000
minCIR 32000
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
Director of CCIE Training and Development - IPexpert, Inc.
Mailto: brian@ipexpert.net
Toll Free: 866.225.8064
Outside U.S. & Canada: 312.321.6924
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Wayne Hines
Sent: Wednesday, April 16, 2003 10:56 PM
To: 'Jonathan V Hays'; 'Brian McGahan'; ccielab@groupstudy.com
Cc: 'Mike Williams'
Subject: RE: MINCIR = CIR?
So, based on this discussion, it would appear that Solie's book requires
a[nother] correction??
!for Darth Reid Lab, P1149, Section III 4.
!FRTS on PVC between R1 R2
!Carrier CIR is 32K, Local Port Speed is 64K
!Solie says
map-class frame-relay mymap
frame-relay cir 32000
frame-relay bc 64000
frame-relay be 0
frame-relay adaptive-shaping becn
!by default
!frame-relay mincir 16
!should this be (assuming Tc=0.125)
map-class frame Shape32
frame traffic-shaping adaptive becn
frame bc 4000
frame be 4000
frame cir 64000
frame mincir 32000
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Jonathan V Hays
Sent: Thursday, 17 April 2003 11:00
To: 'Brian McGahan'; ccielab@groupstudy.com
Cc: 'Mike Williams'
Subject: RE: MINCIR = CIR?
> -----Original Message-----
> From: Brian McGahan [mailto:brian@cyscoexpert.com]
> Sent: Wednesday, April 16, 2003 1:33 PM
> To: 'Jonathan V Hays'; ccielab@groupstudy.com
> Cc: 'Mike Williams'
> Subject: RE: MINCIR = CIR?
>
[snip]
> The following formulas hold true for Cisco's
> implementation of Frame-Relay Traffic Shaping:
>
> Bc = (CIR * Tc)/1000
> Be = ((AR - CIR) * Tc)/1000
>
Brian,
What units are you using to require division by 1000? Most Cisco
documents seem to give Bc= CIR * Tc.
http://www.cisco.com/en/US/tech/tk713/tk237/technologies_configuration_e
xample09186a00800942f8.shtml
See the document I cited in my earlier post (included above) under
"Nonconfigurable parameters - interval (Tc)" -
--- "The time interval during which you send the Bc bits in order to maintain the average rate of the CIR in seconds.Tc = Bc/CIR in seconds.
The range for Tc is between 10 ms and 125 ms." --- In the example given in the Cisco document, Bc is 8000 bits, CIR is 64000 bps, then Tc = 8000 bits / 64000 bps = 1/8 second.
Or if you use Bc = CIR * Tc, then Bc = 64000 bps * 1/8 second = 8000 bits.
What does dividing by 1000 get me?
Thanks.
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