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Re: Ideally BER should be a customer controlled option

At 1:04 AM -0700 5/31/99, Rich Taborek wrote:
>I have to disagree with you on this one.
>Ethernet is a highly successfull data transport in part because of its
>inherent simplicity and scalability. The simplicity, in turn, results
>from developing standards with very few options. I'm afraid that making
>BER a customer controlled option is a step in the wrong direction.

I also agree that BER should not be a "field configurable" parameter. From
the perspective of the higher layer protocols, the physical channel should
"work" to a high degree of probability. That is, the BER should be as low
as possible, given practical and economic constraints. Users have enough
"dials to twiddle" that can screw up their networks without adding
configurable physical channel behavior.

>As for scalability, the BER, being essentially proportional to the frame
>error rate due to transmission link noise, has scaled along with
>increases in throughput. It only makes sense to scale BER
>objectives/frame error rate objectives for 10 GbE.
>Setting a BER objective of 10 E-13 may be reasonable and cost effective
>for the following reasons:

As I stated earlier, I believe that any error goals should be formulated as
a *frame loss rate* (FLR), measured at the Physical Layer service
interface, rather than a BER. This will eliminate any issues about error
propagation due to coding variations, symbol errors vs. bit errors, etc.

Rich Seifert                    Networks and Communications Consulting
seifert@xxxxxxxxxx              21885 Bear Creek Way
(408) 395-5700                  Los Gatos, CA 95033
(408) 395-1966 FAX
"... specialists in Local Area Networks and Data Communications systems"