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Perspective
The power of Ethernet
By Glenn Bischoff
August 1, 2007
Power over Ethernet technology, which lets users power communications
devices using the same standard Ethernet cable that transports data to
and from those devices -- saving them a ton of money in the process and
giving them more control over those devices (see stories below) -- is
going to take off. Metcalfe's Law says so.
Robert Metcalfe, a co-inventor of Ethernet -- the standard that makes
it
possible for computers to communicate with each other over short
distances -- and the founder of 3Com, once opined that the value of a
telecommunications network is directly proportional to the square of
the
number of users on the network.
Consequently, the convergence of devices on IP networks is going to
accelerate, said Zeus Kerravala, senior vice president of The Yankee
Group.
"Right now, in any building, you have HVAC systems, fire-alarm systems,
a bunch of different things, all on separate networks. I think you'll
eventually see all of those things converge on a single network," he
said.
One of the big advantages of such convergence is that it brings a
measure of intelligence that today is lacking, according to Kerravala.
"When you put everything on one network, you can connect them all," he
said. "For instance, let's say your fire-alarm system is registering
something, and you have your thermostats on the same network. So, you
might be able to understand where a fire started, which might help you
decide how to send people in and where they need to go. The more things
you can put on the network, the more intelligence you can gather about
what's happening on the network."
Given this convergence, it doesn't take a genius to figure out that
vendors of technology that lets users power devices for pennies on the
dollar, gives them greater control over their networks and devices, and
provides vital information that wasn't available before, are in a great
position to cash in. That position is strengthened by IP's stature as
the kingpin of communications, a stature it likely will keep for
decades
to come.
As Kerravala astutely pointed out when I spoke with him this week,
"There's no doubt that IP has won. People don't remove IP from their
buildings. There will never be less IP. It's only going to grow."
I couldn't agree more. There are many whose opinions I deeply respect
who still are skeptical about IP from a voice perspective. But I've
witnessed firsthand just how far the technology has come, and
eventually
IP voice will be suitable for mission-critical communications. It's
only
a matter of time -- and probably not too much time, in the grand of
schemes. When it occurs, the advantages borne of converging all voice,
data and video devices on a single network will be too compelling to
ignore. Just ask Robert Metcalfe.
E-mail me at gbischoff@mrtmag.com.
ADVERTISEMENT
 Phihong
lowers the cost of PoE with a complete range of midspans (1 - 24 ports)
that
provide a full 15.4 watts of power per port. No additional power
management
required. Prices
starting at $29.95.
Features
A many splendored
thing
By Glenn Bischoff
August 1, 2007
Ubiquity isn't always a good thing, which was very apparent in this
summer of the 17-year cicada, as anyone who had one of the creatures --
some seemingly as large as small birds -- splatter their windshield and
obliterate their field of vision can attest.
But in the communications world, ubiquity often is a very good thing,
particularly when it comes to Ethernet cable, which literally is
everywhere. Communications providers for the past 5 years or so
have been turning to power-over-Ethernet technologies to bring
electricity to field installations, for pennies on the dollar. And with
next-generation standards on the horizon -- the trend is expected to
accelerate...
(Click on the link above or scroll down for the full-length
feature)
More power to you
By Donny Jackson
August 1, 2007
Over the past several years, power over Ethernet (PoE) technology has
become commonplace, most often used to supply DC electricity to
voice-over-IP phones and wireless access points, so each device only
requires one physical link -- an Ethernet cable -- instead of also
needing a power cord.
While the 12.95 watts per device generated by 802.3af -- the existing
PoE standard -- is enough to power simpler versions of these devices,
it
is not enough to work with feature-rich devices such as video phones
and
multiradio, multimode access points that have become common in the
market. To address this market need, the IEEE has established a task
force to develop a higher-powered PoE standard...
(Click on the link above or scroll down for the full-length
feature)
Mariners test the
PoE waters
By Mary Rose Roberts
August 1, 2007
U.S. cargo vessels crossing vast oceans are targets for motivated
terrorists and unforeseen natural disasters. In order to safeguard this
crucial element of American commerce and military support, the U.S.
Department of Transportation's Maritime Administration, or MARAD,
recently tested power over Ethernet (PoE) for wired and wireless
networks that support fleet communications from ship to shore...
(Click on the link above or scroll down for the full-length
feature)
ADVERTISEMENT
 Phihong developed its range of
high-power PoE midspans to meet the coming IEEE802.3af standard. Full
power in every port, 30W per port, with 1, 4, 8 and 16 ports available.
No power
management required. Prices starting at
$39.95.
Features (Full-Length)
A many splendored thing
By Glenn Bischoff
August 1, 2007
Ubiquity isn't always a good thing, which was very apparent in this
summer of the 17-year cicada, as anyone who had one of the creatures --
some seemingly as large as small birds -- splatter their windshield and
obliterate their field of vision can attest.
But in the communications world, ubiquity often is a very good thing,
particularly when it comes to Ethernet cable, which literally is
everywhere. Communications providers for the past 5 years or so
have been turning to power-over-Ethernet technologies to bring
electricity to field installations, for pennies on the dollar. And with
next-generation standards on the horizon (see story below) -- the trend
is expected to accelerate.
Four pairs of wires exist in a standard Ethernet cable, with two of
those pairs used to transport data. The other two pairs were unused --
until someone got the bright idea that they could be used to transport
electricity. PoE today is being used to power wireless access points,
video surveillance cameras and VoIP phones, amongst other devices.
The cost savings are startling, according to Keith Hopwood, vice
president of marketing for Phihong. "When you have to put a device into
a location where there aren't any power outlets, it can cost you $1000
and up for each access point or camera," Hopwood said. "You have to get
an electrician to run the power, install the conduit and outlets. It's
even more expensive in wet locations."
PoE costs far less, making it a superior option for enterprises with
large campuses, such as universities and colleges, as well as retailers
that are providing Wi-Fi connectivity to customers and thus need to
deploy dozens, hundreds or even thousands of hotspots.
"One of our PoE injectors, instead of spending a thousand dollars, it
only costs 25 dollars," Hopwood said. "You're installing an adapter
that
lets you run power over the Ethernet cable, instead of hiring an
electrician to run conduit. It's all labor costs -- it's not the
materials. It will take an electrician two hours to run the conduit and
wiring. With PoE, you place the device in the closet, and you're done."
There are other cost savings, according to Jamie Cassano, sales manager
for Hyperlink Technologies. "You no longer have to do battery backup,"
he said. "Generators, charging systems and maintenance on the batteries
and the batteries themselves ... are not a cost-effective solution."
There are other advantages beyond cost savings to using Ethernet to
deliver power. For instance, data captured by video surveillance
cameras
can be backhauled over the same cable that's being used to provide the
juice. The voltage is low enough, Cassano said, that users don't have
to
worry about electromagnetic energy seeping out and corrupting the data
-- which is particularly important to the law-enforcement sector, which
needs assurances that any footage captured is admissible as evidence in
a court of law.
"[PoE right now is limited] to 48 volts, and that's pretty low
current,"
Cassano said. "Everything that we have working in our homes runs on 12
volts, and you don't get any interference. PoE is just four times that.
PoE really is just a big extension cord, when you start to think about
it, where you have data running over certain pairs of lines, and power
running over the other pairs."
Mike Pula, product line manager at Panduit, agreed that data corruption
isn't something that should concern PoE users. "The beauty of carrying
high-speed data transmissions over twisted pair is that the twists of
the cable prevent the egress of data [from] the cable," Pula said. "But
if there are concerns, going to a shielded twisted pair, which adds an
element of foil or braided shield, would [prevent] any sort of seepage,
both coming into the cable, or going out."
There are other advantages to PoE. Because many video-surveillance
cameras on the market today -- including wireless cameras -- contain an
Ethernet port, PoE can be used not only to power the device but to
control it, Pula said.
"When you think about a wireless camera, you think, 'Why do I need data
connectivity?' But the data connectivity can be there for program
logic,
setup or instructions to that camera," he said. "If that camera gets
out
of tune or out of sync with the location that it's monitoring, it may
need some adjustments. So you may want to use that [data
connectivity]... to do corrective actions or perform resets on that
camera. Having the dual purpose of data communications as well as power
to those devices can serve the field very well ... because it gives you
a backdoor method of getting to these devices."
That represents another significant cost savings for an enterprise,
according to Zeus Kerravala, senior vice president for The Yankee
Group.
"You can use PoE to push configuration updates to the device, or simply
turn it on or off," he said. "The alternative is a truck roll, and a
truck roll costs several hundred dollars at a time."
Kerravala added that PoE also lets users gather intelligence about the
devices, a useful tool. "You can do diagnostics off it, or tell whether
the device has been tampered with."
Also, PoE lets users place wireless access points in optimal locations,
as opposed to those that are most convenient, according to Pula.
"Many times, the outlet that may be closest may not be the best outlet
for that particular application," he said. "For instance, the
facilities
person or electrician may note that there was an outlet mounted -- it
might be for a clock -- down the hallway, and it could be 20 feet away
from the optimal position for the access point. But because that outlet
is there, sometimes the decision is made to put the wireless access
point there because it's convenient and they don't have to do another
electrical run."
Such a decision can have a detrimental effect on the access point's
range, as well as the integrity of the signal it transmits.
"In a campus environment, the optimal position may be so that anyone
walking down the corridors or in a classroom would have almost equal
access to the same degree of signals coming from that access point,"
Pula said. "Put in a 15- to 20-foot difference, and you may experience
dropouts, or you may experience a null location, where -- if you sit in
a corner of the classroom -- you may get either poor or no reception."
More power to you
By Donny Jackson
August 1, 2007
Over the past several years, power over Ethernet (PoE) technology has
become commonplace, most often used to supply DC electricity to
voice-over-IP phones and wireless access points, so each device only
requires one physical link -- an Ethernet cable -- instead of also
needing a power cord.
While the 12.95 watts per device generated by 802.3af -- the existing
PoE standard -- is enough to power simpler versions of these devices,
it
is not enough to work with feature-rich devices such as video phones
and
multiradio, multimode access points that have become common in the
market. In addition, 802.3af does not supply enough power for
increasingly popular digital surveillance cameras that can be remotely
controlled to pan, tilt and zoom.
To address this market need, the IEEE has established a task force to
develop a higher-powered PoE standard -- PoE+, or 802.3at -- that is
expected to deliver at least 30 watts of power to devices. And being
able to power such devices with PoE can be a significant cost savings
to
an enterprise, said Bob Grow, chairman of the IEEE's 802.3 working
group.
"One of the places where DC power is very effective is where the cost
of
getting AC power to the device is quite expensive," Grow said. "For
many
of the devices you're installing, getting the AC power to the device is
more expensive than the device itself."
Keith Hopwood, vice president of marketing at PoE vendor Phihong,
echoed
this sentiment.
"People have discovered that, 'Wow, now I can put up a wireless access
point or a security camera on a wall somewhere, and I don't have to
spend hundreds -- or thousands -- of dollars to pay an electrician to
install that device, because I can just run it from the data cable,'"
he
said.
This flexibility is possible because the IEEE task force does not risk
pushing the safety limits of the category 5 cabling that is a
prerequisite to PoE, said Wael William Diab, secretary of the IEEE
802.3
working group.
"One of the nice things is that, when you're running power over
Ethernet, you don't have to have an AC power line dropped, which means
the IT guy can do the installation as opposed to a very expensive
person
coming in to drop the power wire," Diab said.
Currently approaching the end of the task-force draft phase, the
proposed 802.3at standard is expected to include dynamic power
allocation, which lets a device seek only the power it needs at a given
moment instead of requiring that its highest possible power level be
met
at all times, Diab said. This feature allows greater power efficiency,
which can mean that additional devices can be powered through the PoE
link.
"In the previous standard, you have to declare your worst-case power up
front. Now, 90% of the time, you may not need that much power," Diab
said. "It's a very powerful concept because it allows you to do so many
things and not have to constantly live within this worst-case power
[scenario] up front."
None of the interviewees were willing to speculate on an ultimate
limitation for PoE, in part because Ethernet technology repeatedly has
exceeded expectations in areas such as data rates and transport
distances.
Of the current challenges, one of the most critical is the wire
temperature of the Ethernet cable, Hopwood said.
"If the standard Ethernet cable goes above 60 [degrees Celsius], the
plastic in them deforms, and basically you start losing data," he said.
"So you don't want the temperature to go above 60 degrees Celsius;
otherwise, the wire's permanently damaged, and you have to rerun the
wire throughout the facility."
This temperature concern is a factor when hundreds of cables are
bundled
in a ceiling space in a hot climate like Phoenix, Ariz., Hopwood said.
Under other circumstances -- for instance, a single dedicated cable in
a
less demanding climate -- it is possible to deliver 200 watts to a
device, he said.
"We're shipping lots of higher-power product because people need it and
they're willing to pay for it," Hopwood said. "They'd love to have a
standard on it, but the standard's not there, so we are delivering
systems that we think are pretty close to the standard or will be
firmware upgradeable to the standard.
"The kinds of things that are really pushing up the power level are
people are running computer work stations off of PoE. The idea there is
that you can have an office that's not constrained by power outlets,
and
you could have a central UPS that backs up all the computers in a call
center, for instance."
While the potential for PoE is great, Grow said the fact that it is a
DC
technology makes it less efficient than AC power, which is a
significant
disadvantage in situations where large amounts of power are needed or
when electricity must be delivered long distances.
"It's DC vs. AC -- it goes back to Westinghouse vs. Edison," Grow said.
"The loss is worse for DC power than it is for AC power."
However, in other scenarios where those factors do not play a
significant role, PoE makes economic sense -- particularly when the
802.3at standard is finalized sometime in late 2008 through mid-2009,
Grow said.
"There's lots of devices that require very low power, and it will
always
be efficient for those devices," he said. "The higher you go in power
consumption, the tougher those tradeoffs get. There will still be lots
of valid applications to use DC power."
Mariners test the
PoE
waters
By Mary Rose Roberts
August 1, 2007
U.S. cargo vessels crossing vast oceans are targets for motivated
terrorists and unforeseen natural disasters. In order to safeguard this
crucial element of American commerce and military support, the U.S.
Department of Transportation's Maritime Administration, or MARAD,
recently tested power over Ethernet (PoE) for wired and wireless
networks that support fleet communications from ship to shore.
MARAD is tasked with the development and maintenance of the U.S.
merchant marine that safeguards waterborne commerce and serves as a
naval and military auxiliary in times of war or during a national
emergency, said Donna Seymour, the agency's chief information officer.
It also ensures the United States maintains adequate shipbuilding and
repair services, efficient ports, and effective intermodal water- and
land-transportation systems for use during a national emergency.
To support these activities, in March 2006 MARAD began a pilot program
that tested wired computer networks embedded with wireless technologies
on 44 of its fleet's vessels. As the project reaches completion,
Seymour
found that outfitting each ship to support logistics systems that
communicate with bases onshore depended on the integration of systems
and how they were powered.
"The Maritime Administration purchased an off-the-shelf, logistics
support system, and we wanted to have better operational support across
our ships in support of our mission," she said. "So we needed to have
better networking and better computers onboard vessels in order to
support that logistics system. This also was an opportunity to network
vessels and update all IT systems onboard."
Stanley Inc. of Arlington, Va., and its subcontractor Federal Concepts
of Stevensville, Md., worked on the project. David MacKinnon, a project
manager at Stanley, said that the wired and wireless networks were
developed to support logistics and management systems. Ships did not
have consistent networks, he said. So the first phase of the project
was
to install common networks on all of the ships, including desktop
computers, servers, wireless access points, routers and a series of
antennas.
However, it was a challenge to deliver power to wireless access points
mounted throughout each ship. Installing power cable became problematic
because older vessels in the fleet had asbestos components, which meant
that drilling and then running new cable would release toxins into the
air.
"Some of our vessels are older: There's asbestos mitigation that
[inspectors] have to do, so the least amount you can drill into any
part
of the ship the better," Seymour said.
To solve the problem, the company turned to PoE, a technology that
transmits electrical power, along with data, to remote devices over
standard twisted-pair cable in an Ethernet network, which makes it
particularly valuable in locations where it would be inconvenient or
infeasible to supply power separately.
"With wired networks aboard the ship, it's much easier to run Ethernet
compared to power cable," MacKinnon said. "The reason is that ships
have
strict wiring and Coast Guard standards about how these things need to
be done. With Ethernet, it's much less complicated and flexible in
terms
of what we are trying to do."
Ships have two circuits for power: one is a dedicated backup with an
emergency generator, and one is a more general-purpose power source.
Dedicated circuits are not available across large vessels. Instead,
they
are located primarily in the control tower where MacKinnon said
critical
systems failure would be disastrous. With PoE, dedicated circuits can
be
extended throughout the entire ship.
"Which makes sense because there's more stability if there's only one
power connector that needs to be kept alive in the event of power
failure aboard the ship," he said.
In addition, Seymour noted, there is a separation between the PoE
system
and other systems aboard the vessel. PoE keeps the power requirements
separate, so if one system goes down there is a system available for
what she calls priorities of power -- critical systems that keep the
ship afloat and protected in times of emergencies.
In addition, the agency installed a remote management gateway dubbed
the
SeaWave Integrator, developed by Middletown, R.I.-based SeaWave. Larry
Zevon, the company's technical product manager, said the system
supports
data transmission and integrates several different communication
technologies. The integrator attaches directly to the ship's network,
Zevon said. No software needs to be installed.
"The Integrator itself is a Linux server," he said. "It assigns an IP
address to all the computers on the vessel. It's really a gateway
device
between ship and shore."
It comes standard with an Imersat voice and data modem as well as
built-in GPS that can be optionally equipped with an Imersat
integrated-services digital network, or ISDN, card, as well as a
quad-band GSM modem. It also supports GPRS/EDGE, which meets the needs
of international clients, and supports external communication devices,
such as a very small aperture terminal for shore networks or WiMAX for
vessels operating inland or at port. Zevon said it selects the least
expensive means to route voice and data. GPS is used to capture the
billing record detail that tracks calls and e-mails transmitted from
the
vessel.
In addition, Iridium short-burst data is used to send real-time,
vessel-tracking data to pre-configured destinations, Zevon said. Users
log into the SeaWave Web site and a personalized page displays data,
such as diagnostic details, speed and heading.
It is one of many technologies MARAD continues to invest in to support
its fleet and to catch up with commercial fleets -- many of which have
already installed high-speed data networks. In fact, the agency's next
pilot program will test mesh networks on groups of ships, which will
let
technicians access computer systems in order to remotely troubleshoot
system failures, Seymour said.
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