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Re: Long distance links


I have always stated that I, as a customer, needed a WAN compatible 10GbE.  That includes the
scramble encoding, the data rate, and the minimal operations support functionality.  The
objectives presented to the HSSG were limited to the MAC data rate only.  Without an effective
9.584 MAC data rate, however it is achieved, there will not be a WAN compatible 10GbE.  As a
customer, I am only one representative of a massive market with a specific need.  The WAN/MAN
market massively enlarged over the LAN only market.  Unless there is a specific agenda on the
part of certain vendors to maintain inflated prices for legacy WAN interfaces, there should be no
reason for a WAN compatible 10GbE to more expensive than the LAN only 10GbE at the same optical

Thank you,
Roy Bynum
MCI WorldCom

Dae Young KIM wrote:

> Roy,
> Now we're close to the point. I do agree the line coding can change.
> But what confuses me is your line of arguments wherein the issue of speed(10.0 vs 9.58) and
> the issue of line coding(Scrambed NRZ) seem to be subtly mixed up, which I think shouldn't
> be. Speed is one thing and Line coding is another.
> Which one is your primary interest? Are you interested in promoting the 9.58 speed or the
> Scrambled NRZ line coding? If it should be the speed, then please stick to it, but please
> don't mix the issue with the line code choice.
> If I'm not wrong, your latest argument says:
>     - SONET is coding sensitive. Even DWDM is coding sensitive. (Install-base Dark Wavelength
> and SOENT is using Scrambed NRZ..?)... NRZ efficiency... So we must have 9.58Gbps speed AND
> Scrambled NRZ...
> Here typically, the two things are unnecessarily mixed. Whatever line code the WAN infra
> (Dark Wavelength, DWDM, SONET) may use, just terminate your Ethernet stream with Ethernet PHY
> and get back the MII data stream and feed this into your WAN infra.
> This so far is one thing: Line Coding
> And yet, if you're not satisfied with the MII data rate which, say, is 10.0Gbps, then you
> proposed a second(WAN-Ethernet) PHY wherein
>     - the HOLD feature is impelmented
>     - the line code is, if you like, the NRZ,
> and ask the Ethernet port at the customer premises Router or Ethernet switch to use this
> WAN-Ethernet PHY. Then this PHY will be very much WAN-infra(Dark Wavelength, DWDM, SONET)
> friendly.
> The same cutomer premises Router or Ethernet Switch might have LAN-Ethernet PHY which might
>     - not have HOLD feature and so operate at exact 10.OGbps
>     - use any (yet to be standardized) line code of which NRZ is of course yet one of the
> candidates.
> This has been another: Speed.
> Roy Bynum wrote:
> > Dae,
> >
> > The line coding for 100BaseFX is different from 1000BaseSX/LX, that did not prevent a
> > change.  Why should it prevent a change with 10000BaseXX?
> --
> Dae Young KIM