Hi Tim,

Thursday, June 29, 2006, 11:32:24 AM, you wrote:

> Patrick Murphy wrote:

>> Okay, I will. She did say something about proprietary compression
>> algorithms, but I'll ask her about milliseconds, next time. Lower
>> latency should result in faster uploading and downloading, if a large
>> file was being sent, right? So I could ask each ISP how long it should
>> take to send, say a 100 MB file?

> Latency refers to the amount of time between when a character or 
> packet of data leaves your network, travels up through the satellite
> and back to Earth and is put back on the rest of the public Internet
> by the satellite service provider. You will probably notice longer 
> latencies more in situations where many smaller packets are sent like
> checking email, filling out web forms, etc. Note that if you are doing
> something where you get a result it takes at least 2 x latency--one 
> for your mouse click, etc. and the other for your result to be returned.

> The compression algorithms used are usually more effective when 
> sending big blocks of data like files. There's a certain amount of 
> "overhead" bytes associated with each packet of data sent. If the 
> packet contains only a few characters or a single mouse click there's
> not much to compress. Most humans feel that they have received an 
> instantaneous response from a machine or system if they get some form
> of feedback or result in under 100mS. Longer than that and the delay
> begins to become perceptable without actual measurement.

> I would stick to asking for an actual time in milliseconds as well as
> information on how they arrived at the figure. In my opinion the more
> open and forthright they are about their benchmark information the 
> higher the probability you would be pleased with the results.

> On our Direcway system no sophisticated measurements are required to
> tell that it is much slower for certain applications like checking 
> email. When your connection is through a terestrial network 
> downloading a hundred emails appears like a continuous stream where 
> they come one after another. Through the satellite connection it's 
> readiliy apparent that each one is being received and acknowledged 
> individually.

> None of this means you should not use any satellite based system. I 
> would look carefully at any claims of my satellite is significantly 
> faster than brand X.

> Tim

Thanks to all of you for helping me understand latency and bandwidth.
The more I learn, the more I realize how little I know. And it's good
to know how inaccurate my assumptions can be. :-)

-- 
Best regards,
Patrick Murphy
James Valley Colony
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