RE: [EFM] RE: OAM Transport Proposal
Kevin,
Bingo! You did a better job of clarifying PMD versus PHY than I did.
Thanks!
Cheers,
Brad
-----Original Message-----
From: Kevin Daines
[mailto:Kevin.Daines@xxxxxxxxxxxxxxxxxxxx]
Sent: Thursday, May 02, 2002 6:27 PM
To: Sanjeev Mahalawat; Booth, Bradley;
stds-802-3-efm@ieee.org
Subject: RE: [EFM] RE: OAM Transport Proposal
Sanjeev,
I'm just commenting on one paragraph of your e-mail,
included below. (Rest of message deleted for everyone but Pat who enjoys
Ethernet in the First Mile :)
--- from Sanjeev e-mail ---
Since 802.3ah is tasked to define new PHYs so I do not see
why a PHY can not be defined
to guarantee to pass a complete preamble to RS and don't see
why specifying so for a PHY
would break 802.3 spec. Correct me if I am wrong, it is not
expected for 802.3ah 1000Mbps
PHY to be compatible with 1000Base-X PHY or 100Mbps copper
PHY to be compatible
with 100Base-T PHY. So, if that is not the case what is the
big issue here?
---
KQD> My reading of and interpretation of the 802.3ah
objectives leads me to believe you are wrong, at least in part. Consider the
following objective:
Provide a family of physical layer specifications:
- 1000BASE-LX extended temperature range optics
- 1000BASE-X >= 10km over single SM fiber
- 100BASE-X >= 10km over single SM fiber
- PHY for PON, >= 10km, 1000Mbps, single SM fiber, >=1:16
- PHY for PON, >= 20km, 1000Mbps, single SM fiber, >=1:16
- PHY for single pair non-loaded voice grade copper distance
>=750m and speed >= 10Mbps full-duplex
Note: This is taken from
http://www.ieee802.org/3/efm/public/mar02/objectives_2_0302.pdf
Yes, EFM is defining new PHYs for PON and for copper.
However, EFM is defining new PMDs - not PHYs - compatible with Clause 36
1000BASE-X PCS and Clause 24 100BASE-X PCS.
So, I believe it IS expected for 802.3ah to be compatible
with 1000BASE-X.
Can this compatibility be achieved through the creation of a
new RS? Can this compatibility be achieved by using a lesser number of
preamble bytes? Can we resolve the issue of MDC/MDIO connectivity? I believe
the answer to each of these is yes. We just need to decide the path the Task
Force is going to take (and give us editors some direction!)
Kevin Daines
Editor, IEEE P802.3ah EFM OAM