CLARION M10II TESTING
GETTING STARTED GUIDE
PAGE 16
versa. Transmit filtering also provides added security because
local server traffic is not exposed to other segments.
c)
Download filtering on: This feature can be thought of as the
converse of transmit filtering. The M10II with this enabled will
not download to its network segment, a packet that it receives if
the destination is not on its local segment. Of course, all packets
on the same code channel will be received by the M10II, and
their CRC will be checked, prior to the address being examined.
d)
Aging = 5 minutes. This default value is the same as in most
bridges. If a NIC is shut down, the aging setting is the time that
it takes to passively decide to remove the entry from the local
table. As long as a packet is sent from a NIC more often than
this setting, the entry will remain in the table. Most network
operating systems will normally send out keep-alive or sense
packets more often than once per minute. The penalty for being
deleted from the table is minimal; it takes about 20 ms
(milliseconds) after a packet is transmitted for the entry to be
placed into the table. Also, if a NIC is moved to another
segment, the transmissions that it generates from another M10II
will force the instant deletion of the NIC address from the table
of the first M10II. If transmissions from the moved NIC are not
received, the aging will cause the NIC to be deleted after the
aging time as measured from the last packet that the NIC
generated while it was still local. The table is volatile and
cycling the power will delete the table.
e)
Loop detection. The M10II has an optional capability for
detecting and blocking network loops. A loop is a network
connection that allows a packet to be regenerated, and can occur
with any wired or wireless network device. An example of a
loop is when two radios are inadvertently connected to the same
network segment, and they are on the same code channel, then a
packet that is uploaded and transmitted by one radio, is received
and downloaded by the second radio, which creates a packet to
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,
