POWER OVER ETHERNET |
over 4 pairs, brings unprecedented robustness
and efficiency to PoE, increasing the
technology’s potential usefulness in ITS.
“Fueled by growing adoption of IEEE
802.11ac wireless access points and a diversity
of emerging applications (encompassing
network-attached storage, building automation,
security, entertainment and more) demand
for PoE-enabled switch ports is expected to
surge to new heights, with 900 million ports
expected to ship during the next five years,”
says Tam Dell’Oro, founder and CEO of
Dell’Oro Group. “With the increase in its
power delivery capacities, combined with its
cost-efficiency, flexibility and scalability, PoE
has evolved as a competitive solution for the
enterprise and consumers alike.”
Educating the market
However, the personnel installing the usually
outdoor equipment used in intelligent
transportation systems are often unaware of
the proper techniques for using PoE and,
therefore, opt to inefficiently run separate
power feeds and/or simply eschew the most
advanced cameras, radios and other
technologies, in order to avoid deployment
and maintenance complexity.
Clarification and guidance are needed
in the space for ITS to take advantage of the
breakthrough value promised by PoE, in terms
of operational flexibility and cost efficiency.
The introduction of an Ethernet Alliance
certification program around the new IEEE
802.bt PoE standard as a commonly trusted
resource among regulators, suppliers, installers
Intertraffic W 094 orld | Annual Showcase 2020
and consumers stands to
facilitate heavier reliance
on PoE in ITS.
Transformative standard
IEEE 802.3bt provides a
standardized, reliable method for using
all four pairs in a twisted pair data cable to
achieve PoE. The innovation of using four pairs
instead of two, in the specified structured
wiring plant to carry power, doubles the
maximum power that can be achieved via PoE.
Essentially, more conductors mean less power
loss, which for four-pair IEEE 802.3bt PoE
along a CAT5 Ethernet cable is roughly halved
versus two-pair power such as that used in
IEEE 802.3af or IEEE 802.3at PoE.
This is a particularly compelling benefit
relative to the outdoor equipment used in
applications such as ITS. Outdoor network
devices such as cameras and radios tend to
require more power than do many indoor
Ethernet devices, and IEEE 802.3btstandardized
PoE delivers.
The standard also provides a combination of
inventive, interrelated techniques for bringing
even more efficient power management to
PoE’s utilization of the same infrastructure
for power and data:
• IEEE 802.3bt defines eight power classes
in 15-Watt increments. A powered device
(PD), such as an end station, requests a
class of power, and the power sourcing
equipment (PSE), such as a switch or hub,
assigns one of the eight class definitions
With the increase in its power delivery capacities,
combined with its cost-efficiency, flexibility, and
scalability, PoE has evolved as a competitive solution
for the enterprise and consumers alike
Tam Dell’Oro, founder and CEO, Dell’Oro Group