Modbus
Cellular
Gateway
Index
skipping
is
used
to
reserve
slots
for
new
function
insertion,
when
required.
76
Tag
‐
based
VLAN
is
also
called
a
VLAN
Trunk.
The
VLAN
Trunk
collects
all
packet
flows
with
different
VLAN
IDs
from
Router
device
and
delivers
them
in
the
Intranet.
VLAN
membership
in
a
tagged
VLAN
is
determined
by
VLAN
ID
information
within
the
packet
frames
that
are
received
on
a
port.
Administrator
can
further
use
a
VLAN
switch
to
separate
the
VLAN
trunk
to
different
groups
based
on
VLAN
ID.
Following
is
an
example.
In
a
SMB
company,
administrator
schemes
out
3
segments,
Lab,
Meeting
Rooms,
and
Office.
In
a
Security
VPN
Gateway,
administrator
can
configure
Office
segment
with
VLAN
ID
12.
The
VLAN
group
is
equipped
with
DHCP
‐
3
server
to
construct
a
192.168.12.x
subnet.
He
also
configure
Meeting
Rooms
segment
with
VLAN
ID
11.
The
VLAN
group
is
equipped
with
DHCP
‐
2
server
to
construct
a
192.168.11.x
subnet
for
Intranet
only.
That
is,
any
client
host
in
VLAN
11
group
can’t
access
the
Internet.
At
last,
he
configures
Lab
segment
with
VLAN
ID
10.
The
VLAN
group
is
equipped
with
DHCP
‐
1
server
to
construct
a
192.168.10.x
subnet.
