From: Vincent Mashburn (vmashburn@fedex.com)
Date: Thu Oct 12 2006 - 10:29:03 ART
The be in "shape average" is an extended burst, but it conforms to the
CIR. This is because the be is sent during a separate clock cycle than
when it was calculated. The "shape peak" sends bc + be every interval
whereas the "shape average" sends bc every interval, but if the entire
bc did not get used, then it flows over to the next available cycle to
be transmitted. This way, you are still conforming to the CIR, but you
get to utilize your bandwidth more efficiently. This is also the reason
that Cisco recommends that you set be to 0 when using VoIP. The be
traffic gets queued until a clock cycle occurs that did not use all of
its bc, and then it gets transmitted. This could cause some serious
latency issues. Hope this helps.
Vince Mashburn
Voice / Data Engineer
901-263-5072
CCVP, CCNP, CCDA,Network +
Cisco IP Telephony Support Specialist
Cisco IP Telephony Operations Specialist
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Michael Zuo
Sent: Wednesday, October 11, 2006 12:51 PM
To: Leon van Dongen
Cc: ccielab@groupstudy.com
Subject: RE: Shape Average command
Thanks the reply.
The Cisco doc says "If the traffic being sent to the network must
strictly conform to the configured network provisioned CIR, then you
should use average traffic shaping."
This sort of leads back to my original question. If the "shape average"
is used to confirm traffic to CIR, what is the purpose of allowing "be"
to be specified? Is there a special scenario the "be" parameter is
needed?
thanks
-----Original Message-----
From: Leon van Dongen [mailto:l.dongen1@chello.nl]
Sent: Sunday, October 08, 2006 4:09 AM
To: Michael Zuo
Cc: ccielab@groupstudy.com
Subject: Re: Shape Average command
Michael,
The shape average command does allow excess burst traffic to be sent
when Be is configured.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/hq
os_r/qos_s1h.htm#wp1085303
HTH
--Leon
Michael Zuo wrote:
> Hi group,
>
>
> i am just curious, if the "shape average" command only allow Bc to be
sent out
> each timing interval, why does it allow user to specify Be parameter?
>
> thanks in advance...
>
>
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