H3C Technologies H3C S5560 Series Switches - Manual (Page 47)

13
Enable MAC address move notifications
The outgoing interface for a MAC address entry learned on interface A is changed to interface B when
the following conditions exist:
• Interface B receives a packet with the MAC address as the source MAC address.
• Interface B belongs to the same VLAN as interface A.
In this case, the MAC address is moved from interface A to interface B, and a MAC address move occurs.
If a MAC address is continuously moved between the two interfaces, Layer 2 loops might occur.. To
detect and locate loops, you can view the MAC address move information.
When the system detects that a MAC address frequently moves from an interface, you can configure
MAC address move suppression on the interface to bring it down. The interface can automatically come
up after waiting for the specified suppression interval. Or, you can manually bring up the interface. To
make MAC address move suppression take effect, you must use this feature together with ARP fast update.
For more information about ARP fast update, see " Enabling ARP fast update for MAC address moves ."
To display the MAC address move records after the device is started, use the display mac-address
mac-move command.
To enable MAC address move notifications:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enable MAC address
move notifications and
optionally specify a
detection interval.
mac-address notification mac-move
[ interval interval-value ]
By default, MAC address move
notifications are disabled.
If you do not specify a detection
interval, the default setting of 1
minute is used.
After you execute this command,
the system sends only log
messages to the information
center module. If the device is
also configured with the
snmp-agent trap enable
mac-address command, the
system also sends SNMP
notifications to the SNMP
module.
3. Set a threshold for MAC
address moves sourced
from an interface within a
detection interval.
mac-address notification mac-move
suppression threshold threshold-value
The default setting is 3.
4. Set a MAC address move
suppression interval. mac-address notification mac-move
suppression interval interval-value
The default setting is 30
seconds.