shape average vs shape peak

From: maureen schaar (maureen.schaar@gmail.com)
Date: Wed Mar 28 2007 - 18:24:13 ART


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



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