Re: [HSSG] BER Objective

[Petar Pepeljugoski <petarp@xxxxxxxxxx>]

Jugnu,

This may work for some applications.
I am not sure if it would be acceptable for Data Center/ HPC.

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

"OJHA,JUGNU" <jugnu.ojha@xxxxxxxxxxxxx>

08/29/2006 01:37 PM

To	Petar Pepeljugoski/Watson/IBM@IBMUS, <STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx>
cc
Subject	RE: [HSSG] BER Objective

All of this raises the following
question:  If this is so hard to measure, how much impact can it really
have in the real world?  Why not back the BER requirement off to 10e-10?
 
 
Regards, 
Jugnu

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From: Petar Pepeljugoski [mailto:petarp@xxxxxxxxxx]
Sent: Monday, August 28, 2006 8:03 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] BER Objective
 

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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