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RE: Straw poll

Title: Straw poll
My grudging vote is for 9.58 Gb/s.
As someone who will be involved in developing the PMD, I am agonizing over this decision. Please allow me to share my agony.
The PMD has to carry encoded data. Therefore, I cannot ignore encoding when voting for a MAC/PLS interface speed. After looking into the crystal ball, my estimate was that 9.58 Gb/s is likely to be implemented in conjunction with scrambled encoding while 10 Gb/s is likely to be implemented in conjunction with 8B10B. I know it does not have to be this way; but that's what my crystal ball told me.
Therefore, by voting for 10 Gb/s, I thought I would be pushing my destiny towards 12.5 Gbaud. Implementing a direct laser drive at 12.5 GBaud (including obtaining those lasers from multiple sources in the market), and controlling performance of receivers is not just 12.5/9.58 times harder; it is much harder.
But scrambled encoding's implications - frame delimiting, for example - for a cost-effective PHY have not been fully discussed yet. Once you lose 8B10B, you lose all the K characters, and a chance to leverage the robust 802.3z implementation. By the time we hack out all the details of scrambled encoding implementation, the PHY will begin to look a little like a POS device, I was afraid. And then there is the jitter issue for PMD design - you really appreciate 8B10B when you remember that it limits the run length to 5.
So the only way to have my cake and eat it too is to lean towards a "non-serial or non-binary" PMD solution (like WWDM or MAS). But sorry, I am not yet ready to go that far. I think the serial solution has a lot of potential.
In the end, the immediate benefit of lower bandwidth (for PMD design) tilted my vote in favor of 9.58 Gb/s.
Thank you.

Vipul Bhatt
Finisar Corporation
274 Ferguson Drive
Mountain View CA 94043
Phone:(650)691-4000 x113
Email: vipul.bhatt@xxxxxxxxxxx


-----Original Message-----
From: owner-stds-802-3-hssg-speed@xxxxxxxxxxxxxxxxxx [mailto:owner-stds-802-3-hssg-speed@xxxxxxxxxxxxxxxxxx]On Behalf Of Thirion, Walt
Sent: Friday, July 02, 1999 5:39 AM
To: 'stds-802-3-hssg-speed@xxxxxxxx'
Subject: Straw poll

Ok group. In one more attempt to see if there is consensus within the ad hoc as represented on this reflector, please vote for one and only one of the following two motions. This straw poll will be conducted by email, so either post your vote to the reflector or send it directly to me.

Proposed motions:

1.    Adopt as an objective:

   "Support speed of 9.58464 Gb/s at the MAC/PLS service interface."


2.   Adopt as an objective:

   "Support speed of 10.000 Gb/s at the MAC/PLS service interface."


Walter Thirion
Level One Communications