[LARTC] Why SFQ does not drops packets

[LARTC] Why SFQ does not drops packets

[Serguei I. Ivantsov]

Hello All!

Please explain me why my class 10:300 does not drops packets?
My class is bounded and isolated - but 8kbit!\x1783bps!!!


class cbq 10:300 parent 10:1 leaf 801b: rate 8Kbit (bounded,isolated) prio 5
 Sent 470737 bytes 388 pkts (dropped 0, overlimits 7465)
 rate 1783bps 1pps backlog 40p
  borrowed 0 overactions 290 avgidle -786633 undertime 612289

--
 Regards,
  Serguei I. Ivantsov

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Re: [LARTC] Why SFQ does not drops packets

[Wingtung.Leung]

On Fri, 1 Jun 2001, Serguei I. Ivantsov wrote:

> Please explain me why my class 10:300 does not drops packets?
> My class is bounded and isolated - but 8kbit!\x1783bps!!!
>
>
> class cbq 10:300 parent 10:1 leaf 801b: rate 8Kbit (bounded,isolated) prio 5
>  Sent 470737 bytes 388 pkts (dropped 0, overlimits 7465)
>  rate 1783bps 1pps backlog 40p
>   borrowed 0 overactions 290 avgidle -786633 undertime 612289

I'm not sure what 1783bps means. If it is "bytes/sec" more packets should
be dropped, if it is "bits/sec", everything seems to be ok.

How do you get that output? Is it documented somewhere, so I can try it?




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Re: [LARTC] Why SFQ does not drops packets

[Ethy H. Brito]

On Fri, 1 Jun 2001, Wingtung.Leung wrote:

> On Fri, 1 Jun 2001, Serguei I. Ivantsov wrote:
>
> > Please explain me why my class 10:300 does not drops packets?
> > My class is bounded and isolated - but 8kbit!\x1783bps!!!
> >
> >
> > class cbq 10:300 parent 10:1 leaf 801b: rate 8Kbit (bounded,isolated) prio 5
> >  Sent 470737 bytes 388 pkts (dropped 0, overlimits 7465)
> >  rate 1783bps 1pps backlog 40p
> >   borrowed 0 overactions 290 avgidle -786633 undertime 612289
>
> I'm not sure what 1783bps means. If it is "bytes/sec" more packets should
> be dropped, if it is "bits/sec", everything seems to be ok.

As a general rule "bps" means bits per second and "Bps" means bytes per second.
I am not shure if it applies here. I should say it does.

Ethy H. Brito         /"\
InterNexo Ltda.       \ /  CAMPANHA DA FITA ASCII - CONTRA MAIL HTML
+(12) 341-6860         X   ASCII RIBBON CAMPAIGN - AGAINST HTML MAIL
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Re: [LARTC] Why SFQ does not drops packets

[Ramin Alidousti]

On Fri, Jun 01, 2001 at 02:41:47PM -0300, Ethy H. Brito wrote:

> On Fri, 1 Jun 2001, Wingtung.Leung wrote:
> 
> > On Fri, 1 Jun 2001, Serguei I. Ivantsov wrote:
> >
> > > Please explain me why my class 10:300 does not drops packets?
> > > My class is bounded and isolated - but 8kbit!\x1783bps!!!
> > >
> > >
> > > class cbq 10:300 parent 10:1 leaf 801b: rate 8Kbit (bounded,isolated) prio 5
> > >  Sent 470737 bytes 388 pkts (dropped 0, overlimits 7465)
> > >  rate 1783bps 1pps backlog 40p
> > >   borrowed 0 overactions 290 avgidle -786633 undertime 612289
> >
> > I'm not sure what 1783bps means. If it is "bytes/sec" more packets should
> > be dropped, if it is "bits/sec", everything seems to be ok.
> 
> As a general rule "bps" means bits per second and "Bps" means bytes per second.
> I am not shure if it applies here. I should say it does.

Usually, when one talks about the bandwidth it always refers to "bit"
not "byte".

Ramin


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Re[2]: [LARTC] Why SFQ does not drops packets

[Serguei I. Ivantsov]

Hello Wingtung.Leung,

Friday, June 01, 2001, 6:58:44 PM, you wrote:

WL> On Fri, 1 Jun 2001, Serguei I. Ivantsov wrote:

>> Please explain me why my class 10:300 does not drops packets?
>> My class is bounded and isolated - but 8kbit!\x1783bps!!!
>>
>>
>> class cbq 10:300 parent 10:1 leaf 801b: rate 8Kbit (bounded,isolated) prio 5
>>  Sent 470737 bytes 388 pkts (dropped 0, overlimits 7465)
>>  rate 1783bps 1pps backlog 40p
>>   borrowed 0 overactions 290 avgidle -786633 undertime 612289

WL> I'm not sure what 1783bps means. If it is "bytes/sec" more packets should
WL> be dropped, if it is "bits/sec", everything seems to be ok.

Looking at the MRTG graph I can say that bps="bytes per second"

WL> How do you get that output? Is it documented somewhere, so I can try it?

To get the list of classes with details use "tc -s class ls dev eth0"
To get the list of qdiscs with details use "tc -s qdisc ls dev eth0"

If you want to check bandwidth consumed with every class use estimator
in class definition "est 1sec 4sec"

WL> tc class add dev eth0 parent 10:1 classid 10:300 est 1sec 4sec \
WL> cbq bandwidth 64Kbit rate \
WL> 8Kbit allot 1514 weight 1Kbit prio 5 maxburst 1 avpkt 1000 \
WL> bounded isolated

After number of tests I come to conclusion that the only queueing
discipline which can DROP packets and thereby throttle bandwith is
TBF. But it does not allow to throttle bandwith dynamically, does not
allow to relocate bandwith between classes:(

Please put me right if I wrong.

-- 
Best regards,
 Serguei                            mailto:admin@gsc-game.kiev.ua



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Re[2]: [LARTC] Why SFQ does not drops packets

[Serguei I. Ivantsov]

Hello Ramin,

Friday, June 01, 2001, 8:41:52 PM, you wrote:

RA> On Fri, Jun 01, 2001 at 02:41:47PM -0300, Ethy H. Brito wrote:

>> On Fri, 1 Jun 2001, Wingtung.Leung wrote:
>> 
>> > On Fri, 1 Jun 2001, Serguei I. Ivantsov wrote:
>> >
>> > > Please explain me why my class 10:300 does not drops packets?
>> > > My class is bounded and isolated - but 8kbit!\x1783bps!!!
>> > >
>> > >
>> > > class cbq 10:300 parent 10:1 leaf 801b: rate 8Kbit (bounded,isolated) prio 5
>> > >  Sent 470737 bytes 388 pkts (dropped 0, overlimits 7465)
>> > >  rate 1783bps 1pps backlog 40p
>> > >   borrowed 0 overactions 290 avgidle -786633 undertime 612289
>> >
>> > I'm not sure what 1783bps means. If it is "bytes/sec" more packets should
>> > be dropped, if it is "bits/sec", everything seems to be ok.
>> 
>> As a general rule "bps" means bits per second and "Bps" means bytes per second.
>> I am not shure if it applies here. I should say it does.

RA> Usually, when one talks about the bandwidth it always refers to "bit"
RA> not "byte".

RA> Ramin


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RA> LARTC mailing list / LARTC@mailman.ds9a.nl
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Well, let's perfom a little calculation :)

"tc -s class ls dev eth0" :

> class cbq 10:200 parent 10:1 leaf 8026: rate 16Kbit (bounded,isolated) prio 5
>  Sent 4049872 bytes 3846 pkts (dropped 0, overlimits 10286)
>   borrowed 0 overactions 1364 avgidle 309677 undertime 0

after 4 second :

> class cbq 10:200 parent 10:1 leaf 8026: rate 16Kbit (bounded,isolated) prio 5
>  Sent 4049926 bytes 3847 pkts (dropped 0, overlimits 10286)
>  rate 13bps
>   borrowed 0 overactions 1364 avgidle 309677 undertime 0

4049926(bytes)-4049872(bytes)T(bytes)

54(bytes)/4(second)\x13.5 BYTES PER SECOND!

It is easy to come to this conclusion when looking at MRTG graps.

-- 
Best regards,
 Serguei                            mailto:admin@gsc-game.kiev.ua



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Re: [LARTC] Why SFQ does not drops packets

[Ramin Alidousti]

On Fri, Jun 01, 2001 at 11:23:46PM +0300, Serguei I. Ivantsov wrote:

> Hello Ramin,
> 
> Well, let's perfom a little calculation :)
> 
> "tc -s class ls dev eth0" :
> 
> > class cbq 10:200 parent 10:1 leaf 8026: rate 16Kbit (bounded,isolated) prio 5
> >  Sent 4049872 bytes 3846 pkts (dropped 0, overlimits 10286)
> >   borrowed 0 overactions 1364 avgidle 309677 undertime 0
> 
> after 4 second :
> 
> > class cbq 10:200 parent 10:1 leaf 8026: rate 16Kbit (bounded,isolated) prio 5
> >  Sent 4049926 bytes 3847 pkts (dropped 0, overlimits 10286)
> >  rate 13bps
> >   borrowed 0 overactions 1364 avgidle 309677 undertime 0
> 
> 4049926(bytes)-4049872(bytes)T(bytes)
> 
> 54(bytes)/4(second)\x13.5 BYTES PER SECOND!

I agree. This is how the *throughput* is measured. What I meant was
when you talk about Ethernet, Fast-Ethernet, Gig-Ethernet, TokenRing,
DS3, OC3, OC48, OC192... all is expressed in bits/sec and that's
the bandwidth. The throughput can be packets/sec or bytes/sec or
bits/sec.

Ramin

> 
> It is easy to come to this conclusion when looking at MRTG graps.
> 
> -- 
> Best regards,
>  Serguei                            mailto:admin@gsc-game.kiev.ua

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Re: Re[2]: [LARTC] Why SFQ does not drops packets

[Wingtung.Leung]

(Please send the the mailing list only .. )

On Fri, 1 Jun 2001, Serguei I. Ivantsov wrote:

> After number of tests I come to conclusion that the only queueing
> discipline which can DROP packets and thereby throttle bandwith is
> TBF. But it does not allow to throttle bandwith dynamically, does not
> allow to relocate bandwith between classes:(
>
> Please put me right if I wrong.

We use a setup without the TBF qdisc, and limit our traffic only using
the rate parameter and seperate classes with cbq. So I think you are
wrong.

But I admit I don't have any good answer to your output. I will try to get
you one early next week.


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