RE: [10GBASE-T] PAR and 5 critters
Forwarded for Dan Dove without attachment... Dan, please give the URL
for the presentation as our website doesn't accept attachments.
Thanks,
Brad
-----Original Message-----
From: "DOVE,DANIEL J (HP-Roseville,ex1)" <dan.dove@hp.com>
To: "'Sterling Vaden'" <sterlingv@bellsouth.net>
Cc: stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] PAR and 5 critters
Date: Tue, 29 Jul 2003 11:17:53 -0700
Hi Sterling,
I have been an outsider to the study group work, so please excuse me if
I am
bringing up an issue that has already been dealt with, but as I
understand
it the current proposals for coding rely upon a spectrum of > 400MHz. It
is
possible that companies manufacturing cable system infrastructure
equipment
like patch panels, wall jacks, and even the cable itself have qualified
their products for FCC and EN compliance based upon measurements done
with
equipment that only uses <100MHz spectrum like 100BASE-T or 1000BASE-T.
That
said, the balance requirements for such equipment may never have been
stressed at frequencies above 100MHz for longitudinal balance, and so
the
installed base of cable systems may have issues with EMI compliance if
someone were to begin running equipment with a PSD that produces large
energy above 100MHz on those systems.
Has any work been done to characterize this issue? I found a
presentation by
Joseph Babanezhad but don't think he applied a full analysis in the
sense
that it appears he did not allow for natural filtering of the output PSD
by
device capacitance and magnetics on the MLT-3 PSD. Check out the
attachment.
Clearly MLT-3 and PAM-5 (100 and 1000 speeds) can operate without energy
above 125MHz and most implementations limit energy above that frequency.
I
believe the 10G designs will require substantially higher energy than
those
technologies in the region 100MHz < f > 400MHz.
Again, please excuse me if this has been addressed. Just point me to the
data.
Regards,
Dan Dove
802.3 member
-----Original Message-----
From: Sterling Vaden [mailto:sterlingv@bellsouth.net]
Sent: Tuesday, July 29, 2003 6:43 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