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RE: shape average vs shape peak posted 03/29/2007
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This link is from Cisco DocCD

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/hqos_r
/qos_s1h.htm#wp1085303

The following example uses peak rate shaping to ensure a bandwidth of 300
kbps but allow throughput up to 512 kbps if enough bandwidth is available on
the interface: 

bandwidth 300
shape peak 512000
 
If "shape peak 512000" is used, the throughput should be up to 2x512k =
1024k. So is it an error here?
If in the lab, question asks to "allow throughput up to 512 kbps", which one
is correct?
shape average 512000
or 
shape peak 512000? 

  _____  

From: Blastmor [mailto:alextols@xxxxxxxxx] 
Sent: Thursday, March 29, 2007 2:32 PM
To: Gary
Cc: maureen schaar; Cisco certification
Subject: Re: shape average vs shape peak


Shape peak is rather useless now.

The case when you can use it, for instance, is when provider allows you to
burst but you are warned that your traffic can be dropped at any time (when
ISP is congested) --> so you can use it when your traffic is 
"steady" for jitter and losses(FTP, SMTP and so on)

HTH


2007/3/29, Gary <liguoyi8@xxxxxxxxx>: 

I am confused by average & peak too.
According to DocCD, the syntax is : shape peak cir
By default be=bc. So the target rate is two times cir.
So when should we use "shape peak" and when should we use "shape average"? 





SY, Alexey