RE: shape average vs shape peak

From: Gary (liguoyi8@gmail.com)
Date: Thu Mar 29 2007 - 01:37:09 ART


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"?

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
maureen schaar
Sent: Thursday, March 29, 2007 5:24 AM
To: Cisco certification
Subject: shape average vs shape peak

Hi group,
When I configure two options:
shape average 256000 32000
shape peak 256000 32000

I see in the show policy-map int output excessive bits for the average
shaping configuration. However, with average shaping, no traffic exceeding
the cir should be allowed. In the 'increment' column, I do see with shape
average that 32000/8=4000 bytes is entered, whereas for shape peak it seems
to be (Bc+Be)/8.

Can anyone clarify? See config and output below.

Maureen

policy-map SHAPE
 class class-default
  shape average 256000 32000
!
W2R4#sh policy-map int
 Serial0/0

  Service-policy output: SHAPE

    Class-map: class-default (match-any)
      11 packets, 275 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any
      Traffic Shaping
           Target/Average Byte Sustain Excess Interval Increment
             Rate Limit bits/int bits/int (ms) (bytes)
           256000/256000 8000 32000 32000 125 4000

        Adapt Queue Packets Bytes Packets Bytes Shaping
        Active Depth Delayed Delayed Active
        - 0 3 171 0 0 no

policy-map SHAPE
 class class-default
  shape peak 256000 32000

W2R4#sh policy-map int
 Serial0/0

  Service-policy output: SHAPE

    Class-map: class-default (match-any)
      16 packets, 421 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any
      Traffic Shaping
           Target/Average Byte Sustain Excess Interval Increment
             Rate Limit bits/int bits/int (ms) (bytes)
           512000/256000 8000 32000 32000 125 8000

        Adapt Queue Packets Bytes Packets Bytes Shaping
        Active Depth Delayed Delayed Active
        - 0 5 278 0 0 no



This archive was generated by hypermail 2.1.4 : Sun Apr 01 2007 - 06:35:53 ART