PoE (Power over Ethernet) Support
SecureStack B2 Installation Guide 1-5
Redundant Power Supply Capability
The
switch
has
power
supply
redundancy
capability
when
connected
to
an
optional
SecureStack
C2RPS
‐
POE
external
redundant
power
supply
(RPS).
If
the
internal
power
supply
fails,
the
RPS
assumes
the
entire
load
of
the
switch
without
interrupting
network
traffic.
The
internal
power
supply
and
RPS
each
have
their
own
AC
power
connection,
which
enables
the
connection
of
each
power
supply
to
a
different
AC
power
circuit
for
additional
AC
power
source
redundancy.
PoE (Power over Ethernet) Support
The
switch
is
802.3af
compliant,
which
means
it
can
provide
power
over
Ethernet
cable
connections
from
its
48,
RJ45
front
panel
connectors
to
PDs
in
the
network.
Power
over
Ethernet
(PoE)
refers
to
the
ability
to
provide
48
Vdc
power
to
a
powered
device
using
the
same
Ethernet
cabling
that
provides
data.
Modern
Ethernet
implementations
employ
differential
signals
over
twisted
pair
cables.
This
requires
a
minimum
of
two
twisted
pairs
for
a
single
physical
link.
Both
ends
of
the
cable
are
isolated
with
transformers
blocking
any
DC
or
common
mode
voltage
on
the
signal
pair.
PoE
exploits
this
fact
by
using
two
twisted
pairs
as
the
two
conductors
to
supply
a
direct
current.
One
pair
carries
the
power
supply
current
and
the
other
pair
provides
a
path
for
the
return
current.
While
several
proprietary
legacy
implementations
of
PoE
have
been
deployed
by
LAN
equipment
vendors,
in
2003
the
IEEE
published
the
IEEE
802.3af
‐
2003
specification,
which
is
part
of
the
802.3
suite
of
standards.
The
switch
is
fully
compliant
with
the
IEEE
802.3af
standard.
It
supports
the
standard
resistor
‐
based
detection
method,
as
well
as
AC
disconnect
capability.
The
switch
is
also
capable
of
supplying
7.5
watts
of
power
to
all
ports
simultaneously.
Support
is
also
provided
for
the
802.3af
‐
defined
maximum
of
15.4
watts.
Each
PD
(Powered
Device)
has
a
PDC
(Powered
Device
Classification)
that
is
transmitted
to
the
switch
for
power
management
purposes.
Table 1
‐
1
on
page 1
‐
5
lists
the
classifications
and
the
associated
power
ranges.
Table 1-1 Powered Device Classifications
Class
Usage
PD Maximum Power Range
Usage
None
Default
0.44 to 12.95 Watts
1
Optional
0.44 to 3.84 Watts
2
Optional
3.84 to 6.49 Watts
3
Optional
6.49 to 12.95 Watts
4
Not Allowed
Reserved for Future Use
Summary of Contents for SecureStack B2 B2G124-48P
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