From: Jim Brown (Jim.Brown@xxxxxxxxxxxxx)
Date: Wed Aug 14 2002 - 16:30:21 GMT-3
Dmitry,
Isn't BE equal to the bits allowed during a single TC interval?
Shouldn't this be set to 32000 when the Cisco CIR is set to 32000 for a
total of 64000 bits per second, equaling the access rate of the port.
In other words, should BE + CIR = Access Rate?
-----Original Message-----
From: Volkov, Dmitry (Toronto - BCE) [mailto:dmitry_volkov@ca.ml.com]
Sent: Wednesday, August 14, 2002 11:39 AM
To: 'MADMAN'
Cc: 'ccielab@groupstudy.com'
Subject: RE: traffic shaping numbers - still unclear !!!
Dave,
About Question Nr 3:
SOLIE:
central site (marlin):
port speed = 1544000 kbps
Remote site 1 (glock):
port speed = 64000 kbps
Remote site 2 (sig):
port speed = 1544000
PVC center -- remote 1 has CIR set by the carrier = 32 kbps
PVC center -- remote 2 has CIR set by the carrier = 512000 kbps
marlin:
map-class frame-relay toGLOCK64Kb
frame-relay adaptive-shaping becn
frame-relay cir 1544000 ?????
frame-relay bc 8000
frame-relay be 64000 ????????
frame-relay mincir 32000
map-class frame-relay toSIG1544Kb
frame-relay adaptive-shaping becn
frame-relay cir 1544000 ?????
frame-relay bc 8000
frame-relay be 64000 ????????
frame-relay mincir 512000
Now look at networkers 2002
Frame Relay Traffic Shaping Terms :
Tc-Committed rate Measurement Interval (Bc/CIR)
Bc-Committed Burst Size
Be-Excess Burst Size
CIR-Committed Information Rate
MinCIR-Minimum Committed Information Rate
Port Speed: 64000 Bps
CIR : 32000 Bps (Average Rate of Traffic Without Congestion)
Mincir: 16000 Bps (Average Rate of Traffic With Congestion)
Bc: 4000 Bps (Amount of Data Sent Per Interval)
Be: 32000 Bps (Amount of Excess Allowed Once Credit Has Built Up) - bps !!!!
????
Be Careful With Bits to Bytes and Bytes to Bits Conversions
Frame Relay Traffic Shaping Example
interface Serial0
ip address 10.10.10.1 255.255.255.0
encapsulation frame-relay
frame-relay traffic-shaping
frame-relay class ccie
Enable FRTS Enable FRTS
map-class frame-relay ccie
frame-relay adaptive-shaping becn
frame-relay cir 32000
frame-relay mincir 16000
frame-relay bc 4000
frame-relay be 32000 ?????????? should be 4000 Because
Be=(AR-CIR)*Tc=(64000-32000)*0.125
Be number of bits during interval Tc
Dmitry
-----Original Message-----
From: MADMAN [mailto:dave@interprise.com]
Sent: Wednesday, August 14, 2002 12:30 PM
To: Volkov, Dmitry (Toronto - BCE)
Cc: 'ccielab@groupstudy.com'
Subject: Re: traffic shaping numbers - still unclear !!!
> 3rd Question: ==========
>
> According to
> http://www.cisco.com/warp/customer/125/traffic_shaping_6151.html and Solie
:
> Be (excess burst) is the number of excess bits to transmit during the
FIRST
> (???) interval (Tc) over and above Bc, once credit is built up.
>
> How Be has to be calculated, when we place Be under "frame-relay be"
command
> :
> How many bits can be send over bc per Tc ?? or
> How many bits can we send over CIR during 1 second (i.e. spread in time)
> ??????
> The difference is 8 times if Tc=125 ms !
>
> Solie example: He did put Be 64000 on page 368 and 398 (so it doesn't look
> like typo) - I absolutely don't understand this.
>
> Can somebody explain that, please !!!
>
> CCO http://www.cisco.com/warp/customer/125/21.shtml said: PEAK = DLCI
> maximum speed = (Bc+Be)/Tc = CIR + Be/Tc = AR
>
> if be=64000 sec and bc =8000 sec that is mean that AR = 576000bits/sec
but
> he mentioned that circuit on the far end only 64K.
>
> http://www.cisco.com/warp/customer/125/traffic_shaping_6151.html gives
the
> following example:
> Circuit speed 192 K, Bc =8000 ; Tc=125, CIR=64000 ====> Be =192000/8 -
8000
> i.e. We can send 16000 bits over Bc 8000 bits during Tc only, which is
equal
> to rate 192K=(16000+8000)/Tc !
>
> So, Be (as parameter in "frame-relay be" command) = bits during interval
Tc
> tabove Bc limited by access rate ???
>
> Networkers 2002
> http://www.cisco.com/networkers/nw02/presos/pws/docs/PS-570.pdf at page
66
> gave wrong number for Be=32000 BPS ??? instead of Be=4000 BITS
Don't have the Solie book, can you phrase the question more concisely?
Dave
>
> Dmitry
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