Loop Prevention - Buffalo BS-GS20 Series User Manual

Chapter 2 Settings

Loop Prevention

Configure loop prevention functionality.
Action
Disable for
MAC Thrashing
LDF
Receive Rate
Received Data Threshold
Note: The loop prevention functionality temporarily disables the port, but will not resolve the loop itself. On
the other hand, the spanning tree functionality blocks the port when a loop is detected and switches the route
automatically to prevent the network from going down. This switch has both functions; use the most appropriate
one depending on your network environment.
Configure the switch's action when a loop is detected.
Ignore
When a loop is detected, the switch will do nothing for the port itself; the diag
LED and loop-detected port's LED will blink for the time configured in [Disable
for] section. If a loop is detected again, it will blink and continue until the loop is
resolved.
Disable port
The switch will disable the loop-detected port for the time configured in [Disable
for] section. At the same time, the diag LED and loop-detected port's LED will
blink for the time configured in [Disable for] section. If a loop is detected again
after the time configured in [Disable for] section is passed, the switch will disable
the loop-detected port and continue until the loop is resolved.
Configure the period to disable the loop-detected port when [Disable port] is
selected as the action.
Check to enable MAC thrashing loop detection method, which assumes that a
loop occurs when the switch's MAC address learn limit exceeds the configured
threshold in one second.
Check to enable LDF loop detection method. The switch will transmit the LDF
packet once per second. If the transmitted LDF packet is received, this will
assume that a loop is occurring.
Note: LDF cannot be used when MSTP is enabled.
Check to enable receive rate loop detection method. If the port's threshold
exceeds the configured receive rate, this will assume that a loop is occurring.
Configure the threshold to assume that a loop is occurring. (1-1000 Mbps)
Note: If the received data threshold value is higher than the ingress bandwidth
value on the "Traffic Control" page, the switch may not be able to detect a loop.
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