Re: PAM-5 4-WDM deskewing
In the original note below you say that you manage deskew in "exactly the same
way as its sister proposal 8b/10b 4-WDM at 3.125 Gbaud". The latest update to
the WWDM proposal presented in Albuquerque by Mr. Del Hanson:
http://grouper.ieee.org/groups/802/3/ae/public/mar00/hanson_1_0300.pdf, slide 9
,shows that deskew is handled by "Hari". Hari has very recently been renamed as
the XAUI/XGXS. Therefore, my conclusion is that your PAM-5 4-WDM uses XAUI/XGXS
I'm trying to figure out how many interface proposals for attaching to the
Reconciliation Sublayer we're up to.
If your presentation uses a totally different interface back to the RS, then
just say do. Don't claim that it's the same when it's different.
Jaime Kardontchik wrote:
> Hello 10G'ers,
> At the end of my presentation in Albuquerque,
> "850nm-4WDM-1.25Gbaud transceiver
> over Multimode Fiber for 10 GbE"
> one of the members in the audience asked me
> about how we manage the deskewing since the
> group velocities of the four streams of data
> are different for different wavelengths.
> PAM-5 4-WDM at 1.25 Gbaud manages the deskewing
> in exactly the same way as its sister proposal
> 8b/10b 4-WDM at 3.125 Gbaud.
> In fact, PAM-5 4-WDM at 1.25 Gbaud shares a lot
> of common with 8b/10b 4-WDM at 3.125 Gbaud,
> because both are 4-WDM systems.
> Hence, encoding, serializing, deserializing
> and decoding of both systems is done exactly in
> the same way, as described in the presentation:
> "10Gig MII update"
> by Howard Frazier
> Kauai, Nov 99
> the only differences being:
> 1) one uses the 1000BASE-X PCS (8b/10b)
> and the other uses the 1000BASE-T PCS
> (scrambling, convolutional and PAM-5 encoding).
> 2) one uses a SERDES at 3.125 GHz and the
> other uses a SERDES at 1.25 GHz
> 3) one uses a baud rate of 3.125 Gbaud
> in the fiber and the other uses a baud rate
> of 1.25 Gbaud in the fiber.
> 4) one uses the K-R characters of the 8b/10b
> to perform byte synchronization at the receiver
> and the other uses the IDLE properties of the
> 1000BASE-T PCS to do the same task.
> Deskewing in PAM-5 4-WDM is handled in exactly
> the same way as deskewing in 8b/10b 4-WDM,
> by realigning the octets of data of the four lanes
> after decoding in the receiver, using the
> low frequency 312.5 MHz clock.
> Also Open Fiber Control is dealt identically
> in both systems, since both are 4-WDM.
> Jaime E. Kardontchik
> Micro Linear
> San Jose, CA 95131
> email: kardontchik.jaime@xxxxxxxxxxx
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