HP 4800G Series Configuration Manual page 1952

use bridge MAC addresses to identify different devices. During the forwarding of Layer 2 packets, if the
destination MAC address of a packet is the bridge MAC address of a device, it means that the packet is
sent to this device.
In an IRF, the bridge MAC address of a member device is called member bridge MAC address. The IRF
communicates with the outside as a single device; therefore, it also has a bridge MAC address, which is
called the IRF bridge MAC address. Typically, an IRF uses the bridge MAC address of the master
device as the IRF bridge MAC address.
You are recommended to configure the preservation time of IRF bridge MAC address properly,
otherwise, network problems will occur:
If a master leaves an IRF to join another IRF or to operate independently and the IRF is configured
to preserve the bridge MAC address permanently, bridge MAC address collision occurs and thus
causes network communication problem.
If the master leaves the IRF because of reboot or link failure and the IRF is configured to change
the IRF bridge MAC address as soon as the master leaves, the unnecessary switch of bridge MAC
address occurs and thus causes flow interruption.
Therefore, configure the preservation time IRF bridge MAC address according to your network status:
Preserve for six minutes: After the master leaves, the bridge MAC address will not change within
six minutes. If the master does not come back after six minutes, the IRF system will use the bridge
MAC address of the newly elected master as that of the IRF.
Preserve permanently: No matter the master leaves the IRF or not, the IRF bridge MAC address
remains unchanged.
Not preserved: As soon as the master leaves, the system will use the bridge MAC address of the
newly elected master as that of the IRF.
Follow these steps to specify preservation time of IRF bridge MAC address:
To do...
Enter system view
Configure the IRF bridge MAC
address to be preserved permanently
after the master leaves
Specify the preservation time of the
IRF bridge MAC address as 6 minutes
after the master leaves
Configure that the IRF bridge MAC
address changes as soon as the
master leaves
The change of the bridge MAC address may cause a temporary flow interruption.
Use the command...
system-view
irf mac-address persistent
always
irf mac-address persistent timer
undo irf mac-address persistent
1-15
Remarks
—
Optional
By default, IRF
bridge MAC
address is
preserved for 6
minutes after the
master leaves.