User`s manual

CLARION M10 SERIES TESTING
M10 SERIES USER’S MANUAL PAGE 38
be uploaded by the first one again. If the loop is allowed to
persist, the packet will be regenerated indefinitely. Instead of
allowing this to happen, all M10IIs will first start in the blocking
mode when they are powered on (if loop detection is enabled).
The blocking mode prevents any packets to be transmitted and
only loop-sense packets to be downloaded. If a loop is detected,
the M10II will block traffic until the loop is eliminated. If after
trying for a few seconds, the radio does not sense a loop, it will
exit blocking mode and proceed with a normal boot cycle. After
that, an attempt to sense loops will be made at 3 second intervals,
and steals 2ms of traffic time each 3 seconds in order to operate.
Since a loop can be created while reconfiguring the wired
network the detection process will occur indefinitely. After the
initial boot, there will be 2 one-second intervals, each signaled by
a pair of LED flashes, and then 5 LED flashes if there is no loop
found. If there is a loop, then the radio will enter a blocking state
where no packets will be transmitted or downloaded, and the
radio will continue to sense the loop at 3-second intervals. After
4 intervals without seeing a loop, the blocking state will be
terminated, the LED will indicate this by flashing 5 times. There
may be additional delays in high traffic conditions (i.e. > 65%
wired side utilization, continuously over the 3 second time
periods).
When in the blocking state, a blocking-message packet is
downloaded to the wired side just prior to the loop test packet.
The blocking message is addressed to broadcast (all Fs), and the
source address is the active address. The loop test packet is
addressed to the sensing M10II’s own MAC_ID independent of
the active address. The source address is the active address.
Therefore, it will have the same source and destination address if
the CONFigAs1 command has been issued.
If you power-up with loop-sense turned off, the power-on
blocking state is not entered and the normal LED flash sequence
is observed. If you power-up with it turned on, the blocking state
is entered upon power-up and must be exited for radio operation.
If CONFigFl0 is issued remotely to a radio that is blocking, the
blocking state is not exited. The radio will suspend any check for
loops and will remain in the blocking state. A remote
CONFigFl1 will put the blocking radio back into normal periodic