3
Addressing
55
All interfaces are logically equivalent
Even
though
the
different
types
of
interfaces
may
be
very
different
in
the
way
they
function,
the
SEG
treats
all
interfaces
as
logically
equivalent.
This
is
an
important
and
powerful
concept
and
means
that
all
types
of
interfaces
can
be
used
almost
interchangeably
in
the
various
SEG
rule
sets
and
other
configuration
objects.
This
results
in
a
high
degree
of
flexibility
in
how
traffic
can
be
examined,
controlled
and
routed.
An
extension
of
this
equivalency
concept
is
that
no
interface
is
assumed
to
be
connected
to
trusted
“inside”
networks
or
to
untrusted
“outside”
networks.
The
administrator
makes
these
decisions
and
implements
security
policies
accordingly.
Interfaces have unique names
Each
interface
in
the
SEG
is
given
a
unique
name
to
be
able
to
identify
and
select
it
for
use
with
other
SEG
objects
in
a
configuration.
Some
interface
types,
such
as
physical
Ethernet
interfaces,
are
already
provided
by
the
SEG
with
relevant
default
names
that
are
possible
to
modify
if
required.
any and core interfaces
In
addition,
the
SEG
provides
two
special
logical
interfaces
that
are
named
any
and
core
.
The
meaning
of
these
are:
•
any
represents
all
possible
interfaces,
including
the
core
interface.
•
core
indicates
that
the
SEG
itself
will
deal
with
traffic
to
and
from
this
interface.
An
example
of
the
use
of
core
is
when
the
SEG
responds
to
ICMP
“Ping”
requests.
When
the
destination
interface
of
an
IP
rule
or
route
is
specified
as
core
,
the
SEG
itself
is
the
ultimate
destination
of
the
traffic.
Ethernet interfaces
The
SEG
supports
Ethernet,
Fast
Ethernet,
Gigabit
Ethernet
and
10
Gigabit
Ethernet
interfaces
as
defined
by
the
IEEE
802.3
standards.
Ethernet frames
With
Ethernet,
devices
send
data
as
Ethernet
frames
and
other
devices
“listen”
to
determine
if
they
are
the
intended
destination
for
any
of
these
frames.
A
frame
is
a
sequence
of
bits
that
specify
the
originating
device,
the
destination
device,
and
the
data
payload
along
with
error
checking
bits.
A
pause
between
the
sending
of
individual
frames
allows
devices
time
to
process
each
frame
before
the
next
arrives.
This
pause
is
progressively
smaller
with
the
faster
data
transmission
speeds.
