From: Surjamukhi Chatterjea (surchatt@cisco.com)
Date: Fri Mar 21 2003 - 00:16:36 GMT-3
Here's what I think, somebody correct me if I am wrong:
Unless they specify Tc value in the question,
Tc=10 msec for voice (meaning Bc=CIR/100)and
Tc=125 msec for data (meaning Bc=CIR/8)
http://www.cisco.com/warp/public/125/traffic_shaping_6151.html
Did they specify in the question whether its voice or data traffic
on the PVC?
-----Original Message-----
From: OhioHondo [mailto:ohiohondo@columbus.rr.com]
Sent: Thursday, March 20, 2003 6:10 PM
To: surchatt@cisco.com; 'Hunt Lee'; ccielab@groupstudy.com
Subject: RE: Traffic shaping values
If they use a Tc of 8, the voice quality will suffer excessive delay and
delay variation. Cisco recommends Tc= 100.
-----Original Message-----
From: Surjamukhi Chatterjea [mailto:surchatt@cisco.com]
Sent: Thursday, March 20, 2003 7:04 PM
To: 'Jerry Haverkos'; 'Hunt Lee'; ccielab@groupstudy.com
Subject: RE: Traffic shaping values
Looks like in this case, they used a Tc of 1/8 sec to arrive at the burst
size.
If we treat this as a question asking for FR traffic-shaping instead of
generic
do you think we should also turn on FRF with the command
"frame-relay fragment 750" under the map-class?
Thanks
Surja
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Jerry Haverkos
Sent: Thursday, March 20, 2003 9:38 AM
To: Hunt Lee; ccielab@groupstudy.com
Subject: RE: Traffic shaping values
Hunt
For Voice Cisco recommends mincir=cir. This is meant to eliminate voice
packets being tagged with the DE bit and periodically dropped by the
"Cloud".
In your case mincir-cir=32000
As you stated Cisco recommends Bc=cir/100. That would be 320 in your case.
This parameter is meant to make Tc much smaller than normal. It is meant to
even out the transmission of real time data to eliminate "jitter".
Excess Burst (Be) should always be 0 for voice, again to keep from
transmitting above the contracted CIR and thus having voice packets tagged
with the DE bit.
If your pvc is for voice, I have no idea where they got their values.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Hunt Lee
Sent: Thursday, March 20, 2003 9:04 AM
To: ccielab@groupstudy.com
Subject: Traffic shaping values
Hi Group,
I bummed into one last question for the day...
R2 --- Frame --- R3
Clockrate on all interfaces are set to 64000
MTU size = 750
CIR between the PVC is 32k
The solution config I got is:-
traffic-shape rate 32000 4000 4000 1000
How did they get to these bc, be & byte limit values?
I have done some research on CCO, and Cisco seems to advice that when doing
traffic
shaping on Voice:
Bc = CIR / 100 = 320
Be = 0
Byte limit = I couldnt find anything on this
Any help would be greatly appreciated.
Regards,
Lee
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