Re: [10GBASE-T] PAR and 5 critters
Sterling
My comments in line. This is a good start.
At 09:42 AM 7/29/2003 -0400, Sterling Vaden wrote:
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.
[Yes I agree.]
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)
[Yup]
ISO Class E (or Cat6) UTP to 50 meters (with
extended limits to 500 or 625 MHz) extended limits TBD by ISO or
TIA
[Yes. I agree. We as IEEE 802.3 do not spec cabling but can ask ISO and
TIA to work on the issue]
ISO Class D (Cat5e) Screened? Perhaps up to 80
meters, but this is grey area.
[Yes. These screened cables exist in Europe. We need to do some work to
figure out the distances that can be supported.]
ISO Class D (Cat5e) UTP? Perhaps up to 40
meters,
[Yes. I think we need some minimal goal for 5E to cover some portion of
the installed base]
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.
[This is a stumbling block but we do not need to solve this to go into
TF. I observe that CX4 passed the hurdle of broad market potential
without any support of installed structured cabling. (And I thank Shimon
for this observation)}
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.
[Yes indeed but as we did with the DMD issue on MM fiber in IEEE 802.3z,
sometimes IEEE 802.3 has to do some serious investigation and push the
technology to be able to move forward.]
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.
[[As our chair has directed several times, people are not supposed to
make claims for vendors in the meetings. But I do note that several folks
who work for other, more optimistic PHY vendors still support moving
forward. We have voted in a tecnical feasibility hurdle into our
timeline. We should execute on that plan and
schedule.]]
//Bruce Tolley
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
Bruce Tolley
Senior Manager, Emerging Technologies
Gigabit Systems Business Unit
Cisco Systems
170 West Tasman Drive
MS SJ B2
San Jose, CA 95134-1706
internet: btolley@cisco.com
ip phone: 408-526-4534
"Don't put your hiking boots in the oven unless you plan on eating them."
Colin Fletcher, The Complete Walker
Bruce Tolley
Senior Manager, Emerging Technologies
Gigabit Systems Business Unit
Cisco Systems
170 West Tasman Drive
MS SJ B2
San Jose, CA 95134-1706
internet: btolley@cisco.com
ip phone: 408-526-4534
"Don't put your hiking boots in the oven unless you plan on eating them."
Colin Fletcher, The Complete Walker