RE: WWDM vs. 10Gb/s serial

["Thirion, Walt" <wthirion@xxxxxxxxxx>]

I agree that 8B/10B provides the error detection, etc., but I hope we
can come up with a coding that is more bandwidth efficient. Wasting 20%
of 10 Gb/s just doesn't seem like a good idea to me.

Walter Thirion
Vice President, Strategic Technology Development
Level One Communications
512-407-2110

-----Original Message-----
From: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
[mailto:owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx]On Behalf Of Rich
Taborek
Sent: Monday, May 10, 1999 2:41 PM
To: bill.st.arnaud@xxxxxxxxxx
Cc: HSSG_reflector
Subject: 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@xxxxxxxxxx
> 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
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