Practical guide to predicting latency effects?

Eric Tykwinski eric-list at
Thu Apr 9 02:41:30 UTC 2020

There is still one in XCode tools.  It’s a alternate download: <>
Of course this is limited to OSX, but it’s there.


Eric Tykwinski
TrueNet, Inc.
P: 610-429-8300

> On Apr 8, 2020, at 10:33 PM, Lee <ler762 at> wrote:
> On 4/7/20, Adam Thompson <athompson at> wrote:
>> I’m looking for a practical guide – i.e. specifically NOT an academic paper,
>> thanks anyway – to predicting the effect of increased (or decreased) latency
>> on my user’s applications.
>> Specifically, I want to estimate how much improvement there will be in
>> {bandwidth, application XYZ responsiveness, protocol ABC goodput, whatever}
>> if I decrease the RTT between the user and the server by 10msec, or by
>> 20msec, or by 40msec.
>> My googling has come up with lots of research articles discussing
>> theoretical frameworks for figuring this out, but nothing concrete in terms
>> of a calculator or even a rule-of-thumb.
> There used to be network simulators that claimed to figure that out for you - eg
>  "Predict application performance using real traffic in a simulated mode"
> I suspect all that died after encryption became the norm, since you
> have to be able to see and understand what's going on before you can
> predict what will happen after changing the network.  Take a look at
>  the date is 2008 and all the references are http://xxx  (or maybe I
> can't search worth beans & missed all the current references)
> Or maybe simulation just got too expensive?  I vaguely recall sitting
> through a few OPNET sales pitches in the early 2000s & people getting
> excited about the product until they found out how much it cost :(
> Regards,
> Lee
>> Ultimately, this goes into MY calculator – we have the usual north-american
>> duopoly on last-mile consumer internet here; I’m connected directly to only
>> one of the two.  There’s a cost $X to improve connectivity so I’m peered
>> with both, how do I tell if it will be worthwhile?
>> Anyone got anything at all that might help me?
>> Thanks in advance,
>> -Adam
>> Adam Thompson
>> Consultant, Infrastructure Services
>> [[MERLIN LOGO]]<>
>> 100 - 135 Innovation Drive
>> Winnipeg, MB, R3T 6A8
>> (204) 977-6824 or 1-800-430-6404 (MB only)
>> athompson at<mailto:athompson at>

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