Draytek Vigor2912 Series, User Manual

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Vigor2912 Series User’s Guide 117
Detect.
Mode – Choose ARP Detect or Ping Detect for the system
to execute for WAN detection. If you choose Ping Detect as
the detection mode, you have to type required settings for
the following items.

Primary/Secondary Ping IP – If you choose Ping
Detect as detection mode, you have to type Primary or
Secondary IP address in this field for pinging.

Ping Gateway IP – If you choose Ping Detect as
detection mode, you also can enable this setting to use
current WAN gateway IP address for pinging.
With the IP address(es) pinging, Vigor router can check
if the WAN connection is on or off.

TTL (Time to Live) – Set TTL value of PING
operation.

Ping Interval – Type the interval for the system to
execute the PING operation.

Ping Retry – Type the number of times that the system
is allowed to execute the PING operation before WAN
disconnection is judged.
MTU It means Max Transmit Unit for packet.
Path MTU Discovery – It is used to detect the maximum
MTU size of a packet not to be segmented in specific
transmit path.
Click Detect to open the following dialog.

Path MTU to – Type the IP address as the specific
transmit path.

MTU reduce size by – It determines the decreasing
size of MTU value. For example, the number specified
in this field is “8”. The maximum MTU size is
“1500”. After clicking the “detect” button, the system
will calculate and get the suitable MTU value such as
1500, 1492, 1484 and etc., automatically.

Detect – Click it to detect a suitable MTU value

Accept – After clicking it, the detected value will be
displayed in the field of MTU.
RIP Protocol Routing Information Protocol is abbreviated as RIP
（
RFC1058
）
specifying how routers exchange routing
tables information. Click Enable RIP for activating this
function.