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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