From: Dennis J. Hartmann (dennisjhartmann@hotmail.com)
Date: Thu Apr 28 2005 - 12:23:44 GMT-3
There's a LOT of confusion over this issue.
Here's the difference between Frame-Relay Traffic Shaping (FRTS) and
class-based shaping (shape command used in the modular qos cli [MQC]):
FRTS can do FRF.12 (VoIP over FRAME and CB-shaping can NOT!!! --->
unless you're running latest and greatest 12.3 T code train).
Class-based shaping CAN adapt to BECN messages and they can ADAPT
FECN messages to the source of the traffic by sending Q.922 FRAME test
frames back to the source (so both sides can throttle their rate).
PLEASE..... NEVER do this in the real world! Adaptive traffic
shaping is a BAD thing. Service provider NNI equipment is running at speeed
of OC-12 (622 Mbps) and above (up to OC-192 ~10Gbps). Their TX and RX
buffers flush VERY fast and you will not receive ANY benefit by throttling
your rate (except for punishing yourself). I have personally heard this
from AT&T and MCI engineers.... And I agree with them. But the CCIE lab is
a different topic, now isn't it.
The configurations that Erick Bergquist posted are not identical and
here's why:
Even though we configured a Bc for the shape adaptive command, we do
not use it. Look at my configurations below and notice that regardless of
whether I set a Bc or a Bc + Be, when I shape to AVERAGE, the result is
always the same (the target and average rate are THE SAME!). But when I
shape to peak (class2), the target rate is DOUBLE the average rate because
I'm allowing bursting. The default setting for the target rate is CIR * 1 +
(Be + Bc). Since the defaults for Bc and Be are both 8000 bytes, 8000/8000
= 1 and 1 + 1 = 2. CIR (768kbps * 2 = 1.536 Mbps [1536000 bps]).
If someone has access to a Smartbits 600 packet generator, I'd love
to see the results of this test.....
WARNING!!!!!! Older versions of IOS would use CIR + Bc when shaping
to average..... 12.2(15T) is what I tested with.
R1#show class-map
Class Map match-all test2 (id 2)
Match none
Class Map match-all test1 (id 1)
Match none
Class Map match-any class-default (id 0)
Match any
R1#show policy-map
Policy Map test
Class test1
Traffic Shaping
Average Rate Traffic Shaping
CIR 768000 (bps) Max. Buffers Limit 1000 (Packets)
Bc 7680 Be 7680
Class test2
Traffic Shaping
Peak Rate Traffic Shaping
CIR 768000 (bps) Max. Buffers Limit 1000 (Packets)
Class class-default
Traffic Shaping
Average Rate Traffic Shaping
CIR 768000 (bps) Max. Buffers Limit 1000 (Packets)
Bc 7680 Be 0
Adapt to 8000 (bps)
Map FECN to BECN
R1#show policy-map int s 0/0
Serial0/0
Service-policy output: test
Class-map: test1 (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: none
Traffic Shaping
Target/Average Byte Sustain Excess Interval Increment
Rate Limit bits/int bits/int (ms) (bytes)
768000/768000 1920 7680 7680 10 960
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 0 0 0 0 0 no
Class-map: test2 (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: none
Traffic Shaping
Target/Average Byte Sustain Excess Interval Increment
Rate Limit bits/int bits/int (ms) (bytes)
1536000/768000 4800 19200 19200 25 4800
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 0 0 0 0 0 no
Class-map: class-default (match-any)
84 packets, 8133 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)
768000/768000 960 7680 0 10 960
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 0 53 8436 0 0 no
R1#
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Erick Bergquist
Sent: Tuesday, April 26, 2005 1:42 AM
To: Brian McGahan; Sean C; Pankaj Madhukar Kulkarni; ccielab@groupstudy.com
Subject: RE: MQC based FRTS
So, comparing MQC to old way:
shape average 768000 7680 0
is same as
map-class frame-relay 128k
frame-relay cir 768000
frame-relay bc 7680
frame-relay be 0
frame-relay mincir 768000
Right?
Would you apply the shape command to all classes under the policy so all
traffic gets shaped the same?
--- Brian McGahan <bmcgahan@internetworkexpert.com>
wrote:
> > 2) If I'm understanding your email correctly, yes,
> there is a command
> to
> > apply BECN shaping to FRTS - but it's not under
> class-map, it's under
> a
> > frame map-class:
> > frame-relay adaptive-shaping becn
> >
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/
> wa
> > n_r/wan_f1g.htm#wp1045936
>
> BECN adapt with MQC based FRTS is enabled with the "shape adaptive"
> command under the policy-map class-map subconfiguration mode.
>
>
> HTH,
>
> Brian McGahan, CCIE #8593
> bmcgahan@internetworkexpert.com
>
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-224-8987 x 705
> Outside US: 775-826-4344 x 705
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>
> > -----Original Message-----
> > From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> > Sean C
> > Sent: Monday, April 25, 2005 7:59 AM
> > To: Pankaj Madhukar Kulkarni;
> ccielab@groupstudy.com
> > Subject: Re: MQC based FRTS
> >
> > 1) The best way I can explain it is still by
> providing what is
> available
> > from Cisco:
> >
>
http://www.cisco.com/en/US/products/sw/iosswrel/ps1834/products_feature_
> gu
> > ide09186a00800800fc.html#1019894
> >
> > In a real-world example, I use peak more when a
> customer has a frame
> port
> > that has a 'high port rate' but a small CIR. IOW
> - some customers we
> > support have a 768 Frame port but only have a 4k
> CIR. We use Peak
> rate
> > values to make sure the customers can use the
> extra BW if available.
> >
> > 2) If I'm understanding your email correctly, yes,
> there is a command
> to
> > apply BECN shaping to FRTS - but it's not under
> class-map, it's under
> a
> > frame map-class:
> > frame-relay adaptive-shaping becn
> >
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/
> wa
> > n_r/wan_f1g.htm#wp1045936
> >
> > 3)Not sure what you are asking.
> >
> > 4) It's applied at the physical interface level:
> >
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/
> wa
> > n_r/wan_f2g.htm#wp1062131
> > You are required to apply the physical command
> even if you are only
> > wanting
> > to shape 1 subinterface. Be wary though:
> > The default committed information rate (CIR) of
> 56K will apply in the
> > following situations:
> >
> > When traffic shaping is enabled (by using the
> frame-relay
> traffic-shaping
> > command), but a map- lass is not assigned to the
> VC
> >
> > When traffic shaping is enabled (by using the
> frame-relay
> traffic-shaping
> > command) and a map class is assigned to the VC,
> but traffic-shaping
> > parameters have not been defined in the map-class
> >
> >
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/
> wa
> > n_r/wan_f2g.htm#wp1062131
> >
> > HTH,
> > Sean
> > ----- Original Message -----
> > From: "Pankaj Madhukar Kulkarni"
> <PankajKu@hclcomnet.co.in>
> > To: <ccielab@groupstudy.com>
> > Sent: Monday, April 25, 2005 1:58 AM
> > Subject: MQC based FRTS
> >
> >
> > > Hi Group,
> > >
> > > I guess this question would have appeared on the
> list earlier, so
> kindly
> > > bear with me. Even after referring to the
> UNIVERCD there is still
> some
> > > grey cells on which I seek your inputs.
> > >
> > >
> > >
> > > 1) What is the difference between "shape
> average" and "shape
> > > peak"?
> > >
> > > 2) Is there any command to enable BECN
> based FRTS?
> > >
> > > 3) "shape adaptive" is used to configure
> the "minCIR"
> parameter.
> > >
> > > 4) "Frame-relay traffic-shaping" command
> isn't required at the
> > > interface level.
> > >
> > >
> > >
> > > Apart from the above points any other inputs
> would be appreciated
> too.
> > >
> > >
> > >
> > > Regards,
> > >
> > > Pankaj K
> > >
> > >
>
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