3com 8807 Reference Guide

Page of 1099
MAC Address Table Management Commands
165
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.
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.