[time-nuts] WWV/WWVH audio simulator?

Hal Murray hmurray at megapathdsl.net
Tue Jan 7 07:22:53 UTC 2014


> No, that's not it. It's a design-by-committee thing. As I recall it, the
> Europeans wanted a 32 byte payload, as then you throw in a 32-byte E1 into
> it, but this was judged to small for datacom which the North American side
> wanted, that wanted a 64 byte payload. 

Thanks.  I hadn't heard the E1 idea before.

The story that I remember was that 32 bytes was small enough so that they 
wouldn't need echo canceling.  The Wiki page on ATM says "With 32 bytes, 
France would have been able to implement an ATM-based voice network with 
calls from one end of France to the other requiring no echo cancellation."

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> That is only the start of the trouble. The real troubles was that they
> designed really stupid leaky-bucket algorithms amongst other things.

I think the real problem was much bigger than that.  There was a mind-set 
collision between the phone company people and the networking people.  
Phone/voice people assume traffic uses a constant bit rate.  (They do play 
statistical games like taking advantage of silence on expensive 
trans-Atlantiic links.)  Networking traffic is bursty.  Not only does a 
packet turn into a burst of cells, but packets often come in clusters.  The 
voice market didn't need much buffering.  Back in those days, buffering was 
expensive, or at least though to be expensive.  So the phone companies bought 
switches without much buffering and then expected the networking guys to act 
like voice circuits.  Basically, networking over ATM was a disaster as soon 
as they tried it.

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This is probably getting off topic for time-nuts.


-- 
These are my opinions.  I hate spam.






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