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Re: WWDM vs. 10Gb/s serial



Bill,

The 1000BASE-X PHY already requires most of the facilities necessary to
meet your requirements. Many implementations have the facilities to meet
ALL of your requirements.
 
- Laser failure notification is not required by 1000BASE-X. However,
many implementations support this indication. Internally, a laser
failure will likely result in an assertion of the Link Failure condition
which may be reflected in the (optional) management Status register. A
laser failure indication, if implemented, is generally signalled much
faster than 10 msec.

- Loss of Signal/RX_Los is required by 1000BASE-X. LOS results in an
assertion of the Link Failure condition which may be reflected in the
(optional) management Status register. 

- One of the side benefits of using a robust block code like 8B/10B is
the error detection capability of the code. 8B/10B provides error
detection via invalid code and running disparity error detection. The
8B/10B error rate corresponds quite nicely to the link BER and may be
used to provide dynamic link BER monitoring. 

--   

Bill St. Arnaud wrote:
> 
> I think most restoral and protection schemes will move to higher protocol
> layers. I don't think the 10xGbE at the PHY layer should be concerned about
> fast restoral.  However we do need very fast notification of laser failure
> on the Tx PHY (< 10 msec) and similarly it would be nice in an ideal world
> to have some tools to monitor loss of  received laser power (DC bias?) on Rx
> PHY .  BER would also be useful, but maybe this should be done at a higher
> level protocol
> 
> Bill
> 
> -------------------------------------------
> Bill St Arnaud
> Director Network Projects
> CANARIE
> bill.st.arnaud@canarie.ca
> http://tweetie.canarie.ca/~bstarn

-- 

Best Regards,
Rich

------------------------------------------------------------- 
Richard Taborek Sr.    Tel: 650 210 8800 x101 or 408 370 9233       
Principal Architect         Fax: 650 940 1898 or 408 374 3645
Transcendata, Inc.           Email: rtaborek@transcendata.com 
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Palo Alto, CA 94303-4305    Alt email: rtaborek@earthlink.net