Sterling,
In my engineering judgment, 10GBASE-T can
be made to work reliably on the ISO Class F channel.
Regards,
Sailesh.
-----Original
Message-----
From: Sterling Vaden
[mailto:sterlingv@bellsouth.net]
Sent: Tuesday, July 29, 2003 9:43 AM
To: stds-802-3-10gbt@ieee.org
Cc: stds-802-3-10gbt@ieee.org
Subject: Re: [10GBASE-T] PAR and 5
critters
OK, I'll bite,
I think it has been "shown" that for the purposes of the PAR and 5
critters, 10G will work over the following:
ISO Class F without ammendment.
ISO Class E (or Cat6) screened or SSTP (with extended limits to 500 or 625 MHz)
extended limits TBD by ISO or TIA
(note that Class D and Class E screened (overall shield) and SSTP (individually
shielded pairs) are commonly installed in Europe, so this is not
a "fantasy cable". Screened cabling is also specified by TIA)
ISO Class E (or Cat6) UTP to 50 meters (with extended limits to 500 or 625 MHz)
extended limits TBD by ISO or TIA
ISO Class D (Cat5e) Screened? Perhaps up to 80 meters, but this is grey area.
ISO Class D (Cat5e) UTP? Perhaps up to 40 meters,
For ISO Class D (Cat5e) there is a basic problem in that the cabling standards
groups are unwilling to standardize (create limits) beyond 100 MHz, or expend
further work on the cabling besides measure it. This poses a very real
difficulty in specifying a protocol that relies upon performance beyond that
specified by the cabling standard. (ask Geoff Thompson) Cabling
manufacturers may decide to forego warranting their cabling systems for such a
protocol.
Also, for the time being, lets pretend that alien crosstalk field testing does
not exist (it doesn't). Also lets pretend that alien crosstalk mitigation
techniques (all, retrofit and new cable designs) for the moment do not exist.
These are considerations for the task group.
Some may also contend that the protocol will run on longer lengths of Cat5e and
Cat6 UTP. If so, that is fine, but it is a matter of dispute, and therefore
cannot be considered. This is also a consideration for the task group.
At the Plenary, on the last day we heard the PHY vendors backpedaling on their
previously stated opiniion that it would run on Class F. If that is the case,
and they insist on this position, then the project is dead. Therefore I propose
that there must be an agreement that the protocol will run on at least Class F
cabling to 100 meters, or we need to start over. If we can agree on that, then
we can move forward to consider the other cabling classes.
Sterling Vaden
Bruce Tolley wrote:
Brad:
Thanks for the follow up.
I am confident that if we can agree on crisp, clear objectives for 10 Gbps
reach and media supported in September that we can get our PAR approved and
move into Task Force mode, which is where the real work begins.
Bruce
At 06:35 PM 7/24/2003 -0700, Booth, Bradley wrote:
Study Group Members,
Just to let others that were not at
the meeting know the outcome of the 802.3 Working Group meeting, the Study
Group will have to complete its PAR, 5 Criteria and Objectives in
November. This gives the Study Group the task of completing the PAR, 5 Criteria
and Objectives in 4 months. This will make our September Interim meeting
extremely important. We will need to complete the effort as much as
possible to pre-submit to the 802.3 Working Group prior to the November
Plenary. November will permit us the ability to modify the PAR, 5
Criteria and Objectives prior to asking 802.3 to put the PAR on the NesCom
agenda. The September Interim meeting will focus on the completion of our
PAR, 5 Criteria and Objectives.
Thanks,
Brad
Chair, 10GBASE-T Study Group
Senior Manager, Emerging
Technologies
Gigabit Systems Business
Unit
"Don't put your
hiking boots in the oven unless you plan on eating them."
Colin Fletcher, The
Complete Walker