RE: MINCIR = CIR?

From: Jeongwoo Park (jpark@wams.com)
Date: Thu Apr 17 2003 - 02:38:17 GMT-3


Hi guys, this is what I configured on the remote router (Cisco 1750) based
on the recent discussion on FRTS.
AT&T provided cir is 256k and port speed is 512k. See if you like it or not.

interface Serial0/0
 no ip address
 encapsulation frame-relay
 no fair-queue
 service-module t1 timeslots 1-8
 frame-relay class SHAPE
 frame-relay traffic-shaping
!
interface Serial0/0.1 point-to-point
 ip address 10.10.10.2 255.255.255.252
 frame-relay interface-dlci 100
!

!
map-class frame-relay SHAPE
 frame-relay adaptive-shaping becn
 frame-relay cir 512000
 frame-relay bc 64000
 frame-relay be 0
 frame-relay mincir 256000

Thanks..

JP

-----Original Message-----
From: OhioHondo [mailto:ohiohondo@columbus.rr.com]
Sent: Wednesday, April 16, 2003 8:08 PM
To: Jonathan V Hays; 'Brian McGahan'; ccielab@groupstudy.com
Cc: 'Mike Williams'
Subject: RE: MINCIR = CIR?

This new equation/explanation for calculating FRTS parameter -- I've never
seen it before. It doesn't make sense with anything I've read on the
subject. How does it relate to the CCO iformation found at:

http://www.cisco.com/en/US/tech/tk713/tk237/technologies_configuration_examp
le09186a00800942f8.shtml

where:
Bc=CIR*Tc
Be= (AR*Tc) - Bc

Where is the source of your information?

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Jonathan V Hays
Sent: Wednesday, April 16, 2003 9:00 PM
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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