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Re: 1000BASE-T PCS question


The question about the BER was originally sent to me, so I felt
obliged to answer it.

You deleted the first sentence of my original email, which said:

"I think that other people might be better qualified than I to handle
this question."

I am glad that someone like you, that is in the 802 since its inception,
is clarifying the BER point. I joined the 802 standards effort only
very lately, specifically in the 1000BASE-T (802.3ab) Task Force.

The objectives of the 1000BASE-T standard are:

    "Bit Error Rate of less than or equal to 10^(-10)"

(see page 40-1, line 31, of the P802.3ab/D6.0)


Jaime E. Kardontchik
Micro Linear
San Jose, CA 95131
email: kardontchik.jaime@xxxxxxxxxxx

Rich Seifert wrote:

> At 9:11 AM -0700 5/27/99, Jaime Kardontchik wrote:
> > ...
> >Ethernet standards deliver a BER of 10^(-10).
> >
> This is simply not true. The BER spec for 10BASE5 is 10^-9. For 10BASE2 and
> 10BASE-T, it is 10^-8. For 100BASE-X and 1000BASE-X, it is 10^-12.
> The BER goals for any higher-speed standard should be determined by the SG.
> Further, BER is really a parameter more relevant to serial transmission
> systems that do not use any block-coding; in such systems it is
> straightforward to map between the BER and the Frame Loss Rate (a more
> significant parameter in a connectionless, best-effort frame delivery
> system). We had long discussions both in Fast Ethernet and 1000BASE-T about
> how many frame errors are generated by a single bit error, the relationship
> between symbol errors and bit errors, etc. In the end, the only observable
> characteristic at the MAC service interface is the Frame Loss Rate. I
> propose that any future standards work use this parameter to characterize
> the error performance of the system, rather than BER.
> --
> 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"