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 id 1Ynvfo-00045P-CL; Thu, 30 Apr 2015 17:07:09 -0400
From: "George Neville-Neil" <gnn@neville-neil.com>
To: "Karlis Laivins" <karlis.laivins@gmail.com>
Cc: "Eggert, Lars" <lars@netapp.com>,
 "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>,
 "grenville armitage" <garmitage@swin.edu.au>
Subject: Re: Congestion Control Modification
Date: Thu, 30 Apr 2015 22:06:58 +0100
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If you want to run some experiments, though, you could look at running 
PTPd
on 3 servers (master, and two slaves) which will get you decent 
synchronization
among the three.  Where decent is less than the typical RTT of a TCP 
packet on a
1Gbps LAN.

Best,
George

On 30 Apr 2015, at 14:48, Karlis Laivins wrote:

> Yes, you are correct, I meant to write "relative OWD". As David Hayes 
> put
> it - "Relative OWD measurements are easier, and clock drift is not 
> usually
> a problem over the time it takes to send and receive an ACK".
>
> Thank you for the correction!
>
> On Thu, Apr 30, 2015 at 4:19 PM, Eggert, Lars <lars@netapp.com> wrote:
>
>> On 2015-4-30, at 15:04, Karlis Laivins <karlis.laivins@gmail.com> 
>> wrote:
>>> I have yet to solve the issue of
>>> how to get the One Way Delay for the ACK message (the time it takes 
>>> ACK
>> to
>>> arrive from receiver of the ACK'ed data sender) correctly.
>>
>> That won't work without synchronized clocks, which you can't really 
>> assume
>> to be present.
>>
>> Lars