M2M
Cellular
Gateway
Index
skipping
is
used
to
reserve
slots
for
new
function
insertion,
when
required.
288
TTL
1.
A
Must
fill
setting
2.
1
to
255
range
Specify
TTL
hop
‐
count
value
for
this
GRE
tunnel.
Keep
alive
1.
Unchecked
by
default
2.
30s
is
set
by
default
Check
the
Enable
box
to
enable
Keep
alive
function.
Select
Ping
IP
to
keep
live
and
enter
the
IP
address
to
ping.
Enter
the
ping
time
interval
in
seconds.
Default
Gateway/Remote
Subnet
A
Must
fill
setting
Specify
a
gateway
for
this
GRE
tunnel
to
reach
GRE
server.
If
the
gateway
uses
its
gateway
IP
address
to
connect
to
the
internet
to
connect
to
the
GRE
server
then
select
Default
Gateway,
otherwise,
specified
a
subnet
and
its
netmask
–the
remote
subnet,
if
the
default
gateway
is
not
used
to
connect
to
the
GRE
server.
The
Remote
Subnet
format
must
be
IP
address/netmask
(e.g.
10.0.0.2/24).
DMVPN
Spoke
Unchecked
by
default
Specify
whether
the
gateway
will
support
DMVPN
Spoke
for
this
GRE
tunnel.
Check
Enable
box
to
enable
DMVPN
Spoke.
GRE
Pre
‐
shared
Key
1.
Unchecked
by
default
2.
Pre
‐
shared
Key
8
to
32
character
length
Check
Enable
box
to
add
pre
‐
shared
key
for
GRE
tunnel
connection.
Enter
a
DMVPN
spoke
authentication
Pre
‐
shared
Key.
Note:
Pre
‐
shared
Key
will
not
be
available
when
DMVPN
Spoke
is
not
enabled.
GRE
NAT
Traversal
Unchecked
by
default
Check
Enable
box
to
enable
NAT
‐
Traversal.
Note:
GRE
NAT
Traversal
will
not
be
available
when
DMVPN
is
not
enabled.
GRE
Encapsulation
Mode
Unchecked
by
default
Specify
GRE
Encapsulation
Mode
from
the
dropdown
box.
There
are
Transport
mode
and
Tunnel
mode
supported.
Note:
GRE
Encapsulation
Mode
will
not
be
available
when
DMVPN
is
not
enabled.
Tunnel
Unchecked
by
default
Check
Enable
box
to
enable
this
GRE
tunnel.
Save
N/A
Click
Save
button
to
save
the
settings.
Undo
N/A
Click
Undo
button
to
cancel
the
settings.
Back
N/A
Click
Back
button
to
return
to
the
previous
page.