Modbus
Cellular
Gateway
Index
skipping
is
used
to
reserve
slots
for
new
function
insertion,
when
required.
71
Its
steps
are:
Pre
‐
state:
After
system
booting
up,
system
tries
to
let
the
WAN
connection
be
alive.
S
1:
When
system
discovers
the
WAN
connection
is
failed.
S
2:
System
starts
to
re
‐
connect
the
WAN
connection
till
connect
successfully
as
same
as
Pre
‐
state.
In
the
"Dial
‐
on
‐
demand"
scenario,
system
will
not
make
the
WAN
connection
until
gateway
receives
an
Internet
accessing
request
from
Intranet.
And
then
the
connection
will
keep
alive
only
when
there
still
is
data
transfer.
If
there
is
no
data
transfer
for
a
period
that
is
longer
than
the
Maximum
Idle
Time,
system
will
disconnect
it
and
let
the
WAN
connection
go
back
to
its
initial
state
–disconnected.
The
scenario
is
shown
in
following
diagram.
Gateway
xDSL
Modem
ISP
DSLAM
Intranet
Primary
DNS,
Secondary
DNS,
DHCP
Servers
101
10
110
00
110
0
0
1
①
Request Coming
②
Start Connecting
③
Disconnect when
idle timeout
Dial-on-
demand
Its
steps
are:
Pre
‐
state:
After
system
booting
up,
the
WAN
connection
is
disconnected.
S
1:
When
an
Internet
accessing
request
is
fed
into
the
gateway
from
the
Intranet.
S
2:
System
starts
to
make
the
WAN
connection
till
connect
successfully.
Keep
the
connection
alive
only
when
there
still
is
data
transfer
to
the
Internet.
S
3:
If
the
WAN
connection
idles
timeout,
system
will
disconnect
it
and
let
it
go
back
to
Pre
‐
state.
At
last,
for
"Manually"
scenario,
system
will
not
make
the
WAN
connection
until
administrator
click
on
the
"Connect"
button
on
the
"Network
Status"
configuration
window.
Please
refer
to
[System]
‐
[Network
Status]
section.
And
then
the
connection
will
keep
alive
only
when
there
still
is
data
transfer.
If
there
is
no
data
transfer
for
a
period
that
is
longer
than
the
Maximum
Idle
Time,
system
will
disconnect
it
and
let
the
WAN
connection
go
back
to
its
initial
state
–disconnected.
The
scenario
is
shown
in
following
diagram.
