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And a "sysctl -a | grep tcp" for the Linux case is also
quite helpful ;-)

Alex

Am 17.08.2011 um 13:50 schrieb Agarwal, Anil:

> Barry,
> 
> Can you also post the details of the policer settings used
> for these tests?
> 
> Is ctcp enabled for Windows 7?
> 
> Anil
> 
> -----Original Message-----
> From: end2end-interest-bounces@postel.org
> [mailto:end2end-interest-bounces@postel.org] On Behalf Of Barry
> Constantine
> Sent: Tuesday, August 16, 2011 4:37 PM
> To: anil@cmmacs.ernet.in
> Cc: end2end-interest@postel.org
> Subject: Re: [e2e] TCP Performance with Traffic Policing
> 
> Hi Anil,
> 
> Attached is a Word document with the sequence charts from Wireshark.
> 
> The 64KB and 128KB window sizes are shown for each OS.
> 
> Thanks,
> Barry
> 
> -----Original Message-----
> From: anil@cmmacs.ernet.in [mailto:anil@cmmacs.ernet.in] 
> Sent: Saturday, August 13, 2011 4:24 PM
> To: Barry Constantine
> Cc: anil@cmmacs.ernet.in; end2end-interest@postel.org
> Subject: RE: [e2e] TCP Performance with Traffic Policing
> 
> Hi Barry:
> 
> Would be glad to see the plots/sequence data in case you would like to
> share them.
> 
> If the cause is burst, then the next interesting question whould be: why
> the same TCP sender reacted quite differetnly to different (standard)
> clients when the policing was in between and normal otherwise.
> 
> Anil
> 
>> Hi Anil,
>> 
>> Your assessments seem reasonable and I will look at the packet
> captures
>> with Wireshark as you suggest.
>> 
>> Also, thanks for pointing me to the old post; it was useful as well.
>> 
>> -Barry
>> 
>> -----Original Message-----
>> From: anil@cmmacs.ernet.in [mailto:anil@cmmacs.ernet.in]
>> Sent: Saturday, August 13, 2011 3:15 PM
>> To: Barry Constantine
>> Cc: end2end-interest@postel.org
>> Subject: Re: [e2e] TCP Performance with Traffic Policing
>> 
>> Hi Barry,
>> 
>> Quite  interesting
>> 
>> I would guess that the different flows (Linux, XP and Win7) in your
>> experiment might have expressed varying bursty patterns, and that
> would
>> have made the policing process to treat these flows differently. A
> time vs
>> sequence plot on either side of the policing box should help to bring
> out
>> the real dynamics.
>> 
>> Also, there was a similar post in e2e almost about a decade ago.
>> http://www.postel.org/pipermail/end2end-interest/2002-June/002154.html
>> 
>> It is worth having a look
>> 
>> Anil
>> 
>>> Hi,
>>> 
>>> I did some testing to compare various TCP stack behaviors in the
> midst
>>> of
>>> traffic policing.
>>> 
>>> It is common practice for a network provider to police traffic to a
>>> subscriber level agreement (SLA).
>>> 
>>> In the iperf testing I conducted, the following set-up was used:
>>> 
>>> Client -> Delay (50ms RTT) -> Cisco (with 10M Policing) -> Server
>>> 
>>> The delay was induced using hardware base commercial gear.
>>> 
>>> 50 msec RTT and bottleneck bandwidth = 10 Mbps, so BDP was 62,000
> bytes.
>>> 
>>> Ran Linux, Windows XP, and Windows 7 clients at 32k, 64k, 128k window
>>> (knowing that policing would
>>> kick in at 64K)
>>> 
>>>               Throughput for Window (Mbps)
>>> 
>>> Platform              32K        64K        128K
>>> --------------------------------------------
>>> Linux                     4.9         7.5         3.8
>>> XP                          5.8         6.6         5.2
>>> Win7                     5.3         3.4         0.44
>>> 
>>> 
>>> Do anyone have experience with the intricacies of the various OSes in
>>> the
>>> midst of
>>> Traffic policing?  I was surprised to see such a variation in
>>> performance,
>>> especially since Windows 7 is supposed to more advanced than XP,
>>> 
>>> I am going to comb through the packet captures, but wondered if
> anyone
>>> had
>>> insight.
>>> 
>>> Thank you,
>>> Barry
>>> 
>>> 
>>> 
>> 
>> 
> 
> 

//
// Dipl.-Inform. Alexander Zimmermann
// Department of Computer Science, Informatik 4
// RWTH Aachen University
// Ahornstr. 55, 52056 Aachen, Germany
// phone: (49-241) 80-21422, fax: (49-241) 80-22222
// email: zimmermann@cs.rwth-aachen.de
// web: http://www.umic-mesh.net
//


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