Chapter 4: Operation
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Page 45
Switching, Address Learning
The LBH21-Series units have address table capacity of 1K
node addresses, and are suitable for use in large networks. They are self-
learning, so that as nodes are added or removed or moved from one
segment to another, the LBH21-Series switch automatically keeps up with
node locations.
An address-aging algorithm causes least-used addresses to fall
out in favor of new frequently used addresses. To reset the address
buffer, cycle power down-and-up.
4.2
Auto-cross (MDI-X), Auto-negotiation and Speed-sensing
The RJ-45 ports support auto cross (MDI or MDI-X) in the
auto-negotiation mode according to the IEEE 802.3z standard. No
crossover cables are needed when connecting the LBH21-Series to
other unmanaged switches, legacy hubs, managed switches, media-
converters etc. Please note that there can be conditions with
managed switches where the switch manager fixes the port settings
via software, and the result of the auto-negotiation is changed in the
managed switch by the manager commands. In such cases, the
10/100/1000 speed or the F/H mode may be affected, but auto-cross
in the LBH21 Switches will still work. The auto cross function cannot
be disabled.
When an RJ-45 cable connection is made, and each time
LINK is enabled, auto-negotiation takes place (except for legacy
products, which do not have auto-negotiation and which go to the
default state accordingly). The LBH21-Series Switch advertises its
capability for 10, 100 or 1000Mbps speed and F/H duplex mode, and
the device at the other end of the cable should similarly advertise /
respond. Both sides will agree to the speed and mode to be used per
the IEEE 802.3z standard. Depending upon the devices connected,
