RE: Here's a new idea:
Dan
I believe there will be a greater impact on *not* engineering this
on the Signaling pairs. Both 10 and 100 Ethernet utilize only two pairs,
not 4 pairs. So a minimum implementation of Ethernet is pairs 2&3,
and nothing knows the wiser. Having power on those signaling pairs
satisfies this minimum implementation. Any other implementation should
ask the following questions:
How many customer sites have split off their 4 pair cabling for an
additional station? Many
How much STP Type 1 and Type 2 is there installed? Lots
The cost of re-cabling these sites is significantly greater than the
cost of the new equipment for VoIP and other such implementations that
will utilize this NEW power capability.
This will prevent the adoption of this committee's effort to whole
customer sites at a time -- which I've never thought was a good
philosophy, but seems to be what's going on here, IMO. This seems like a
very exclusionary position, not inclusionary (which is how a standard
should be).
<off soapbox>
for now.....
;-)
At 12:39 PM 5/1/2000 -0700, DOVE,DANIEL J (HP-Roseville,ex1)
wrote:
>
>Hi James,
>
>It occurs to me that the detection method is irrelevant to
>1000BASE-T operation as the link will not be up at the
time
>of operation. However, the issue at hand is whether you
can
>inject power at a mid-span in a way that is compatible
with
>1000BASE-T signalling requirements.
>
>There have been some votes on this subject and my
recollection
>is certainly not the best thing to rely upon, but I recall
>that 10/100T is a MUST while 1000BASE-T is a WANT.
>
>Using pins 4,5 and 7,8 minimize the potential impact on
10/100T
>but would likely have an impact on 1000BASE-T.
>
>There are studies underway to understand just how much
these
>impacts are and whether they will exclude 1000BASE-T
operation.
>
>Regards,
>
>Dan Dove
>___________
_________________________________________________________
>_________ _/
___________ Daniel
Dove Principal Engineer
__
>_______
_/ ________
dan_dove@xxxxxx LAN PHY Technology __
>_____
_/
______ Hewlett-Packard
Company
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>____ _/_/_/ _/_/_/
_____ Workgroup Networks
Division
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>____ _/ _/ _/ _/
_____ 8000 Foothills Blvd. MS
5555
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95747-5555
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>
>-----Original Message-----
>Sent: Monday, May 01, 2000 10:11 AM
>To: Bob Bell; tal@xxxxxxxxxxxxxx;
stds-802-3-pwrviamdi@xxxxxxxx
>Subject: Re: Here's a new idea:
>
>
>Bob
>
>
>It's Monday, so forgive this clarification, but are you asking
Tal to test
>his scheme on the signaling pairs of a 10/100BASE connection as
well as pins
>4/5/7/8 on a 1000BASE-T connection? If not, I'd be curious if
Tal could do
>this; if so.... then I'm being redundant again redundant
again......
>
>
>At 10:18 AM 5/1/2000 -0600, Bob Bell wrote:
>>
>>Tal -
>>
>>One of the objectives the group stated was to test for
powerablity on the
>>same wires as the power would be provided. In addition, it
is desirable
>>that the powering and thus the testing be done in such a
manner that the
>>signal carrying capability of the wire pairs not be
compromised (this it to
>
>>allow it to work with 1000BaseT. Could your scheme meet
these two
>requirements?
>>
>>Bob Bell
>>
>>At 02:27 4/30/2000, Tal Weiss wrote:
>>
>>>Hi all,
>>>
>>>Since this is my first contribution to the forum and I'm
not sure that
>this
>>>email forwarding system works, I'll be brief.
>>>
>>>I read the different discovery process approaches and I
want to offer
>>>something completely different!
>>>
>>>All of the proposals in the forum are analog by nature,
and lack in
>>>"security".
>>>
>>>I was able to construct a digital
"power-identity-chip", costing less than
>>>1$, to be implemented inside the powered-IP-phone. This
was done using
>>>off-the-shelf parts.
>>>
>>>The chip is powered remotely from the switch using 5
Volts (a simple 5K
>>>pull-up resistor does the trick).
>>>
>>>The power-enabled-switch polls the line for
"power-identity-chip" (this
>can
>>>be done across wires 4,5 or 7,8) and when a phone is
attached the chip is
>>>found (CRC protected communication, of course).
>>>
>>>This chip then tells the switch what it's power
requirements are!
>(Voltage,
>>>which wires, power, MAC address and so on...)
>>>
>>>The power-enabled-switch then applies the correct power
using the correct
>>>wiring!
>>>
>>>This approach has been tested in the lab and works using
different cabling
>>>schemes from more than 200 meters!
>>>
>>>No false alarms and no misses.
>>>
>>>I know this is different than all the other approaches
mentioned above,
>but
>>>it works so well I couldn't resist sharing.
>>>
>>>If more information is needed I'll be glad to supply
it!
>>>
>>>Tal.
>>>
>>>--------------------------
>>>Tal Weiss
>>>Congruency Ltd.
>>>23 Hasivim St.
>>>POB 7813
>>>Petah-Tikva 49170, Israel
>>>Email: tal@xxxxxxxxxxxxxx
>>>Phone: 972-3-9212322-218
>>>Fax : 972-3-9210757
>>>--------------------------
>>>
>>
>>Bob Bell
>>Cisco Systems Inc.
>>801-294-3034(v)
>>801-294-3023(f)
>>
>
>
>*************************************
>"At the end of the day... the most committed
win!"
>
>
>James M. Polk
>Sr. Product Manager, Multiservice Architecture and
Standards
>Enterprise Voice Business Unit
>Cisco Systems
>Dallas, Texas
>w) 972.813.5208
>f) 972.813.5280
>
*************************************
"At the end of the day... the most committed win!"
James M. Polk
Sr. Product Manager, Multiservice Architecture and Standards
Enterprise Voice Business Unit
Cisco Systems
Dallas, Texas
w) 972.813.5208
f) 972.813.5280
www.cisco.com