[Nut-upsdev] Idea: UPS id via powerline broadcast

[Stuart D. Gathman]

On Thu, 1 Sep 2011, Charles Lepple wrote:

> On Sat, Aug 27, 2011 at 8:19 PM, Stuart D Gathman <stuart at bmsi.com> wrote:
>> The problem:
>>
>> We maintain small servers in customer offices.  Customers often get
>> confused when asked to plug the server into the UPS.  Sometimes they
>> have multiple servers from different vendors, and multiple UPSs, and
>> plug our server into the wrong UPS.  The end result is that the UPS
>> being monitored with NUT is often *not* the UPS the server is actually
>> plugged into.
>>
> Hmm, interesting.
>
> There are actually a number of network-over-power-line devices that
> relay entire Ethernet packets, so I wonder if there is a "lite"
> version of the MAC/PHY chips which could be used to send that ID.
>
> If the UPS and power supplies provided a full network link, the NUT
> protocol could run over that as well, keeping it out of the regular
> traffic on the other network interfaces. Discovery could be done with
> mDNS and DNS-SD.

Just ran into this again.  Customer had generators for week long power outage
from Irene.  "Be sure to plug the UPS into the generator, and leave your
computer plugged into the UPS." says I.  Well, to them the generator was a kind
of "UPS", so unknown to me, they unplugged from the UPS and plugged into the
generator.  UPS monitoring looked fine - but the system kept crashing.  "Oh, we
have to stop the generator every hour to refuel."  (...bangs head on desk.)

If you have a full network link, you wouldn't need a USB hookup.  Perhaps
that is what you meant by "NUT protocol"?  You meant the protocol between
the nut driver and the UPS.

That would indeed be an additional draw for the feature.  One less cable
to hook up.  And more certainty that the UPS you are monitoring is
the one your power is actually coming from.  A small USB device to slip
into the power supply socket - or maybe a custom power cord - could
be used to addon the capability to a server.  A UPS manufacturer could
offer this now, with the receiving USB device/powercord included, and it
would be an attractive feature to me at least.  It would be
completely compatible with existing USB monitors.

With a USB interface in the power cord, that leaves the manufacturer
the option of using any powerline protocol they wish, since the
monitoring device never sees it.

The above could also be done with an SNMP protocol over ethernet 
if going with the ethernet over powerline protocol as you were
suggesting.  But I think USB would be better - you don't want
a shared network - you want a dedicated interface to the power
device so you know you are talking to the source of your power.

--
 	      Stuart D. Gathman <stuart at bmsi.com>
     Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.