Re: [HSSG] BER Objective

[Petar Pepeljugoski <petarp@xxxxxxxxxx>]

I agree with Howard. It is impractical
and expensive to test for very low BERs - the specs should be such that
the power budget is capable of achieving BER =1e-15, yet the testing can
be some kind of accelerated BER at lower value that is derived from the
curve interpolation.

However, the as with any extrapolation
of testing results one has to be careful, so in this case it will be manufacturers'
responsibility to guarantee the BER=1e-15.  

Regards,

Petar Pepeljugoski
IBM Research
P.O.Box 218 (mail)
1101 Kitchawan Road, Rte. 134 (shipping)
Yorktown Heights, NY 10598

e-mail: petarp@xxxxxxxxxx
phone: (914)-945-3761
fax:        (914)-945-4134

Howard Frazier <hfrazier@xxxxxxxxxxxx>

08/28/2006 05:39 PM

Please respond to
Howard Frazier <hfrazier@xxxxxxxxxxxx>

To	STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
cc
Subject	Re: [HSSG] BER Objective

For the 100 Mbps EFM fiber optic
links (100BASE-LX10 and 100BASE-BX10)
we specified a BER requirement
of 1E-12, consistent with the BER requirement
for gigabit links. We recognized
that this would be impractical to test in a 
production environment, so we
defined a means to extrapolate a BER of 1E-12
by testing to a BER of 1E-10 with
an additional 1 dB of attenuation.  See
58.3.2 and 58.4.2.
 
Howard Frazier
Broadcom Corporation

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From: Roger Merel [mailto:roger@xxxxxxxxxxx]
Sent: Monday, August 28, 2006 1:54 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] BER Objective

David,
 
Prior to 10G, the
BER standard (for optical communications) was set at 1E-10 (155M-2.5G).
 At 10G, the BER standard was revised to 1E-12.  For unamplified
links, the difference between 1E-12 and 1E-15 is only a difference of 1dB
in power delivered to the PD.  However, the larger issue is one of
margin and testability (as the duration required to reliably verify 1E-15
for 10G is impractical as a factory test on every unit) especially since
we’d want to spec worst case product distribution at worst case path loss
(cable+connector loss) and at EOL with margin.  Thus in reality, all
products ship at BOL from the factory with a BER of 1E-15 and in fact nearly
all will continue to deliver 1E-15 for their entire life under their actual
operating conditions and with their actual cable losses.
 
Thus, if by “design
target”, you mean a worst case-worst case with margin to be assured at
EOL on every factory unit, then this is overkill.  I might be willing
to entertain a 1E-13 BER as this would imply that same number of errors
per second (on an absolute basis; irrespective of the number of bits being
passed; this takes the same time in the factory as verifying 1E-12 at 10G
although this is in fact a real cost burden which adversely product economics);
however, this would not substantially change the reality of the link budget.
 It would make for a sensible policy for the continued future of bit
error rate specs (should their be future “Still-Higher-Speed” SG’s).
 
-Roger

 

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From: Martin, David (CAR:Q840) 
Sent: Friday, August 25, 2006 12:22 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: BER Objective
 
During the discussion on Reach Objectives
there didn’t appear to be any mention of corresponding BER. 
 
Recall the comments from the floor during
the July meeting CFI, regarding how 10GigE has been used more as infrastructure
rather than as typical end user NICs. And that the application expectation
for 100GigE would be similar. 
 
Based on that view, I’d suggest a BER design
target of (at least) 1E-15. That has been the defacto expectation from
most carriers since the introduction of OC-192 systems. 
 
The need for strong FEC (e.g., G.709 RS),
lighter FEC (e.g., BCH-3), or none at all would then depend on various
factors, like the optical technology chosen for each of the target link
lengths.

...Dave

David W. Martin
Nortel Networks
dwmartin@xxxxxxxxxx
+1 613 765 2901 (esn 395)
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