3Com 8807 Command Reference Manual page 167

Use the undo mac-address max-mac-count enable forward command to
enable the switch to drop the packets whose source MAC addresses are not
learned by the port when the number of MAC addresses automatically learned by
the port reaches the threshold value.
Use the mac-address max-mac-count enable alarm command to enable the
switch to send alarms to the network administrator when the number of MAC
addresses automatically learned by the port reaches the threshold value.
Use the undo mac-address max-mac-count enable alarm command to remove
this configuration.
By default, the switch forwards the packets whose source MAC addresses are not
learned by the port when the number of MAC addresses automatically learned by
the port reaches the threshold value.
After the mac-address max-mac-count enable { alarm | forward }* command
is executed, if the MAC addresses learned by a port reach the maximum number
of MAC addresses that the port can learned, the port will send an alarm to
network administrator to prompt that the port will no longer learn any MAC
addresses.
Related commands: mac-address, mac-address timer.
n
The maximum number of MAC addresses on an I/O Module ranges from 12 K
■
to 16 K depending on various software versions and module types.
The aforementioned number of MAC addresses includes only the MAC
■
addresses learned by the switch dynamically, and excludes those configured by
the user.
When executing the mac-address max-mac-count command, if the current
■
number of MAC addresses exceeds the threshold value, the switch neither
delete the present MAC address entries nor learn new MAC address until the
number of entries less than the threshold value after some entries are aged
out.
Example
# Set the maximum number of MAC addresses learned by Ethernet port
Ethernet3/1/3 to 600, and the switch will give an alarm to the network
administrator and forward the packets when the number of MAC addresses
learned exceeds 600.
<SW8800> system-view
System View: return to User View with Ctrl+Z.
[SW8800] interface Ethernet3/1/3
[3Com-Ethernet3/1/3] mac-address max-mac-count 600
[3Com-Ethernet3/1/3] mac-address max-mac-count enable forward alarm
# Set the maximum number of MAC addresses learned by Ethernet3/1/3 to 600.
When the number of MAC addresses exceeds this value, the switch drops the
packets whose MAC addresses are not learned by the port.
<SW8800> system-view
System View: return to User View with Ctrl+Z.
MAC Address Table Management Commands 165