[e2e] TCP Performance with Traffic Policing

[Barry Constantine]

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 at cmmacs.ernet.in [mailto:anil at cmmacs.ernet.in] 
Sent: Saturday, August 13, 2011 3:15 PM
To: Barry Constantine
Cc: end2end-interest at 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
>
>
>