Advantech FWA-1320 User Manual page 40

LAN bypass allows automated or manual control of the connectivity between two
LAN ports grouped into a bypass segment and the host:
Figure 2.13 Connectivity options of LAN ports in a bypass segment
In "connect" mode, the ports on a segment are connected to the host via NICs. Traffic
will enter and leave the ports just like on a regular NIC.
In "disconnect" mode, the ports are disconnected from the host and from each other.
No traffic can flow through the ports
In "bypass" mode, the two ports are disconnected from the host, but connected to
each other. Traffic entering the system on one port will be sent out on the other port
and vice versa.
"Bypass mode" is used to allow traffic to flow through the system when the system is
in a non operational state such as loss of power or in case the application is unre-
sponsive. Application health is monitored by a configurable watchdog.
"Disconnect" mode is typically used to block any traffic until the system has fully
started up and the application SW is in a well defined state allowing to handle traffic
properly.
Connectivity can be auto controlled by a number of system events:

Power Up
Host system is turned on / powers up (DC on)

Power Down
Host system is turned off / powers down (DC off)

Power Reset
Host system is reset or rebooted

Watchdog Start
LAN bypass watchdog is started or strobed for the first time

Watchdog Timeout
LAN bypass watchdog timed out

External Trigger
Global Watchdog Trigger input (dedicated GPIO pin)
In addition to the event driven model, it is also possible to set the connectivity for a
bypass segment via the SW API.
2.5.3.1 LAN Bypass Segments
The FWA-1320 supports four onboard traffic ports which are grouped into 2 bypass
segments as shown below:
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