From: Petr Lapukhov (petr@internetworkexpert.com)
Date: Wed Jul 05 2006 - 12:57:38 ART
Chris,
so did devel guys tell you anything on shape peak? :) As to my
tests it always shapes up to "target" rate, i.e. with shape peak
64000 we get limit of 128000 :)
I actually was unable to run iperf, and did all the measurements
with ping/load-interval/show int. Platform 3640, IOS 12.3(14)T.
2006/7/5, Chris Lewis <chrlewiscsco@gmail.com>:
>
> Shape average does not allow Bc + Be to be sent every interval.
>
> Shape average allows Be to be sent in addition to Bc on the first interval
> of a second only, also the shaper needs to have built up credit in
> previous
> intervals to use Be. The effect of Be in shape average is to allow the
> shaper to achieve CIR over a long period of time, accommodating periods of
> lull where less than CIR is sent in one second, with an additional Be
> amount
> of data in a later period should the credit be available and the shaper
> needing to send more data.
>
> Chris
>
>
> On 7/4/06, Joe Gagznos <joegagznos@comcast.net> wrote:
> >
> > I am trying to find another way to limit outbound traffic through an
> > interface similar in manner to policing. I understand that functionally
> > the
> > two are different. With shaping you are going to be queuing excess
> > traffic
> > to a predetermined rate where with policing you are going to be
> executing
> > some kind of action on traffic that exceeds the contract (usually
> > dropping).
> >
> > For comparison purposes, I have configured shaping and policing on two
> > separate subinterfaces in the following manner:
> >
> > interface Ethernet0/0.1
> > encapsulation dot1Q 10
> > ip address 10.1.1.1 255.255.255.0
> > service-policy output shape
> >
> > interface Ethernet0/0.2
> > encapsulation dot1Q 20
> > ip address 10.1.2.1 255.255.255.0
> > service-policy output police
> >
> > Both interfaces are configured to limit traffic to no more than 2.5 Mbps
> > as
> > follows:
> >
> > policy-map police
> > class class-default
> > police 2500000 conform-action transmit exceed-action drop
> >
> > policy-map shape
> > class class-default
> > shape average 2500000
> >
> > What I find is that the shaping interface initializes the parameters as
> > follows:
> >
> > R1#sh policy-map interface e0/0.1
> > Ethernet0/0.1
> >
> > Service-policy output: shape
> >
> > Class-map: class-default (match-any)
> > 19 packets, 1729 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)
> > 2500000/2500000 15000 60000 60000 24 7500
> >
> > Adapt Queue Packets Bytes Packets Bytes Shaping
> > Active Depth Delayed Delayed Active
> > - 0 19 1729 0 0 no
> >
> > A couple things to note here - Be is initialized to the same value as Bc
> > of
> > 60000 (or 7500 bytes). The byte limit is 15000 bytes, though. This
> must
> > mean that the byte limit is initialized to Bc+Be=15000. With a 24 ms
> > interval, does this mean that the interface will send 5 Mbps (15000 * 8
> > bits
> > / byte * 1 sec/.024 = 5000000) instead of the contracted 2.5 Mbps? If
> > shape average is allowing the interface to transmit Bc+Be each interval,
> > then how does this differ from configuring shape peak which accomplishes
> > the
> > same thing?
> >
> > With policing it appears that things are much more straightforward.
> >
> > R1#sh policy-map int e0/0.2
> > Ethernet0/0.2
> >
> > Service-policy output: police
> >
> > Class-map: class-default (match-any)
> > 107 packets, 7473 bytes
> > 5 minute offered rate 0 bps, drop rate 0 bps
> > Match: any
> > police:
> > cir 2500000 bps, bc 78125 bytes
> > conformed 63 packets, 4305 bytes; actions:
> > transmit
> > exceeded 0 packets, 0 bytes; actions:
> > drop
> > conformed 0 bps, exceed 0 bps
> >
> > Thanks for any response!
> >
> > Joe Gagznos
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
-- Petr Lapukhov, CCIE #16379 petr@internetworkexpert.comInternetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Outside US: 775-826-4344
This archive was generated by hypermail 2.1.4 : Tue Aug 01 2006 - 07:13:46 ART