Very Computer

Hi

I was wondering about the WoL feature on some NICs. As far as I understand
it, WoL is a feature of the NIC and connects via a wire to  a connector
on a motherboard that supports this feature.

Ok so if I have a motherboard without this feature am I SOL? Or can linux
support a similar function in software? I am thinking of some sort or
power-down/power-up function that kicks in when there is activity on the
subnet. What about cards that don't have this feature, can they still be
used for this purpose?

MTIA

Bill

                    Small is beautiful. Keep it simple.

Quote:>Ok so if I have a motherboard without this feature am I SOL?

Quote:>Or can linux support a similar function in software?

Quote:> I am thinking of some sort or
>power-down/power-up function that kicks in when there is activity on the
>subnet. What about cards that don't have this feature, can they still be
>used for this purpose?

Quote:> Ok so if I have a motherboard without this feature am I SOL? Or can
> linux support a similar function in software?

Quote:> I am thinking of some sort or power-down/power-up function that kicks
> in when there is activity on the subnet. What about cards that don't
> have this feature, can they still be
> used for this purpose?

regards Henrik
--
spammer strikeback:

 >> I was wondering about the WoL feature on some NICs. As far as I
 >> understand it, WoL is a feature of the NIC and connects via a wire to
 >> a connector on a motherboard that supports this feature.

 >I haven't used it, but this is the way I understand it also.

Yup - a wire to the ma'board.  I looked into it awhile back & saved  a
few scraps of info:

   Wake-On-LAN mode: Supports Magic Packet Wakeup

   ACPI mode: Supports -
     o PCI bus Power Management Interface Spec. (Rev 1.1)
     o D0, D1, D2, D3hot, and D3cold, 5 different power states
     o PMEB (including LWAKE) can be generated from D1, D2, D3hot,
       and D3cold
     o Magic Packet Wakeup
     o LinkUP wakeup
     o Microsoft Wakeup frame

From this I conclude the ma'board's design & BIOS must implement a
bunch of ACPI stuff, then you'd need software to send a magic packet
of the appropriate flavor.  Sounds easy, but I also found the
following:

   Notes regarding tulip chip net cards from:
     http://cesdis.gsfc.nasa.gov/linux/drivers/tulip-devel.html

   Long Term Development Issues:

     o Implement the Wake-On-LAN capability available in 21143. The driver
       part is easy, but the kernel support requires writing extensive APM
       interface code.

I argued with myself over which is better - a lan wakeup capability,
or leave the system running with UPS power backup & power management
[esp. disk & monitor] tuned appropriately.  I haven't come to a
definitive [for me] conclusion as yet...:-)

--
<> Robert Geer & Donna Tomky  |               *             <>


<> Salt Lake City, Utah  USA  |   O/ O     __ /__,    />    <>

Thks,
Bill:)

                    Small is beautiful. Keep it simple.

Just a couple of followup questions regarding WOL:

   * What happens if you send the magic packet while the target
     machine is up and running?  Will it reboot?

   * What if the machine is down for reasons other than a deliberate
     shutdown (like OS crash or being victimized by a denial of
     service attack)?  If the machine does not respond to a ping
     and the magic packet is issued, can the machine be expected to
     power up as expected?

I've been looking around at the IBM, Intel, and APM sites, but
have not found language to give me an answer.

TIA.

Karl