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RE: [10GBASE-T] Power Down mode


At 10:56 AM 8/6/2003 -0700, Booth, Bradley wrote:

>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.

Sorry, could not resist. :) Since when we have a MAC per sub group? Isn't
it 802.3 MAC, a LIVING 802 DOC and LIVING MAC. -:) Having 802.3ae not
support half-duplex makes a separate 802.3ae MAC?

Let the experts jump.

>  Although EFM is using half duplex in
>an interesting way to stall the MAC, we haven't seen anything like that
>proposed for 10G.

EFM has done lots of interesting things. :)


>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.
>-----Original Message-----
>From: Hugh Barrass []
>Sent: Wednesday, August 06, 2003 12:27 PM
>To: Fakterman, Boris
>Subject: Re: [10GBASE-T] Power Down mode
>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.
>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
> >
> >
> >