RE: [10GBASE-T] Power Down mode
Pat-
At 10:46 AM 8/7/2003 -0600, pat_thaler@agilent.com wrote:
Brad and Hugh,
If someone is actually planning to make changes to the MAC, that has
always been something that was wrung out in Study Group as was the half
vs full duplex decision. The efficiency issues of 1 Gig half-duplex were
covered in Study Group.
If someone was seriously proposing half-duplex or if we were to have
technical feasibility or market potential discussion that relied on an
assumption of half duplex, then it would have to be discussed
now.
What seems to me to be a much more serious issue is the extent to which
10GBASE-T will be of an architecture that supports multi-speed,
multi-duplex operation. I.e. which upper interface will it be spec'd to?
What limitations will that put multiple configurations>
Geoff
Pat
-----Original Message-----
From: Booth, Bradley
[mailto:bradley.booth@intel.com]
Sent: Wednesday, August 06, 2003 12:43 PM
To: stds-802-3-10gbt@ieee.org
Subject: RE: [10GBASE-T] Power Down mode
Thanks Hugh! We definitely agree on that point... and especially
about
overtaking EFM. ;-)
Cheers,
Brad
-----Original Message-----
From: Hugh Barrass
[mailto:hbarrass@cisco.com]
Sent: Wednesday, August 06, 2003 2:40 PM
To: Booth, Bradley
Cc: stds-802-3-10gbt@ieee.org
Subject: Re: [10GBASE-T] Power Down mode
Point taken!
I think that the discussion should return to the PAR+5. We have seen
that there are many interesting topics that we can discuss
AFTER WE START THE TASK FORCE!
(sorry for the shouting, but I think we are in danger of putting the
cart before the horse).
We need to agree that the project is worth submitting and after the PAR
is approved we can entertain many interesting proposals for the
project.
Nobody is pretending that it will be easy and I expect that we will
have
to weigh a number of proposals before we can find the right baseline
for
this project.
Don't forget, we need to get the PAR ready for the November plenary if
we are to stand any chance of overtaking the EFM project :-)
Hugh
Booth, Bradley wrote:
>Hugh,
>
>Not if you comply with 4.2.7.5 in 802.3ae. :-) There is no
"may" in
>there as far as half duplex and 10G are concerned.
>
>Cheers,
>Brad
>
>-----Original Message-----
>From: Hugh Barrass
[mailto:hbarrass@cisco.com]
>Sent: Wednesday, August 06, 2003 2:14 PM
>To: Booth, Bradley
>Cc: stds-802-3-10gbt@ieee.org
>Subject: Re: [10GBASE-T] Power Down mode
>
>
>Brad,
>
>I was waiting for the fireworks to start :-)
>
>My tongue was in my cheek when I suggested half-duplex, particularly
>seeing how unpopular it was for Gig. One point though, the MAC for
>10GBASE-T may support HD if it has to work in 10/100/1000/10G autoneg
>mode...
>
>Hugh.
>
>Booth, Bradley wrote:
>
>
>
>>Hugh,
>>
>>What is half duplex? :-) Seriously though, before all the
other
>>
>>
>802.3ae
>
>
>>and 10GbE experts jump on you, there is no half duplex in
10GbE. The
>>802.3ae MAC is full duplex only. Although EFM is using half
duplex in
>>an interesting way to stall the MAC, we haven't seen anything
like
that
>>proposed for 10G.
>>
>>Let's see if we can get the PAR, 5 Criteria and Objectives done
first,
>>then we can toy with other concepts to reduce power or data
rate.
>>
>>Thanks,
>>Brad
>>
>>-----Original Message-----
>>From: Hugh Barrass
[mailto:hbarrass@cisco.com]
>>Sent: Wednesday, August 06, 2003 12:27 PM
>>To: Fakterman, Boris
>>Cc: stds-802-3-10gbt@ieee.org
>>Subject: Re: [10GBASE-T] Power Down mode
>>
>>
>>
>>Boris,
>>
>>This would only really be useful for battery powered equipment.
Most
>>systems will be required to sustain maximum rate traffic and
therefore
>>the idle periods will be less than 1% of the time.
>>
>>Another possibility is half-duplex. If the pre-coding and
pre-emphasis
>>is balanced well with the equalization & decoding then it may
be
>>possible to make a half-duplex transceiver consuming half the
power of
>>
>>
>a
>
>
>>full-duplex one. Of course there may be problems with collision
radius
>>
>>
>&
>
>
>>bursting, but this could enable some early implementations to use
HD
>>while the boffins are working on power reduction
techniques.
>>
>>Hugh.
>>
>>Fakterman, Boris wrote:
>>
>>
>>
>>
>>
>>>Hello all,
>>>
>>>Following the discussion regarding power, it looks like there
is a
>>>consensus that the 10Gb Phy dissipated power will be very
high at
>>>first silicon and relatively high at advanced future
versions.
>>>
>>>The average power is important for most problematic topics,
such as
>>>thermal conditions, power source availability and so
on.
>>>
>>>The average power can be reduced by using the Power-Down
mode. The
>>>transceiver does not transmit or receive data during
significant
>>>periods of time. Instead of transmitting idle symbols while
consuming
>>>full power, the system can enter the Power-Down mode. The
transmitter
>>>power can be reduced by stopping the transmission, the
receiver power
>>>can be reduced as only minimal receive functions will be
active. The
>>>overall dissipated power during the Power-Done can be reduced
>>>significantly.
>>>
>>>Of course there are algorithmic issues to solve, such as how
to
>>>maintain the synchronization during the Power-Down mode, but
these
are
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>>technical problems that can be discussed and solved.
>>>
>>>The average power with implemented Power Down mode depends on
the
>>>length of idle periods.
>>>
>>>The desktop/laptop PC transmits idles most of the time ( >
90% ?). I
>>>don't know what happens in data centers.
>>>
>>>.If we can reduce even half of the dissipated power by the
Power Down
>>>mode, it is worth to be considered.
>>>
>>>Regards,
>>>
>>>Boris Fakterman - Intel Communications Group, Israel
>>>
>>>Tel: 972-4-865-6470, Fax: 972-4-865-5999
>>>
>>>mailto:boris.fakterman@intel.com
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
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