Re: Long distance links
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
http://ccl.chungnam.ac.kr/~dykim/