H3C Technologies H3C S10500 Series Switches - Manual (Page 13)

Each member is managed by its active MPU, which records its known topology information locally. At the
startup of a member switch, the active MPU of the member switch records topology information of the
member switch. When an IRF port of the member switch is up, the active MPU of the switch performs the
following operations:
1. Periodically sends its known topology information from this port.
2. When receiving the topology information from the directly connected neighbor, it updates the
local topology information.
3. If a standby MPU is available on the member switch, the active MPU synchronizes its recorded
topology information to the standby MPU to ensure consistent topology information on both
boards.
After all member switches have obtained topology information (known as topology convergence), the
IRF fabric enters the role election stage.
Master election
Master election is held each time the topology changes, for example, when the IRF fabric is established,
a new member switch is plugged in, the master switch fails or is removed, or the partitioned IRF fabrics
merge.
The master is elected based on the following rules in descending order:
• The current master, even if a new member has a higher priority. (When an IRF fabric is being
formed, all member switches consider themselves as the master, and this rule is skipped)
• The switch with higher priority.
• The switch with the longest system up-time. (The member switches exchange system up-time in the
IRF hello packets.)
• The switch with the lowest bridge MAC address.
The IRF fabric is formed on election of the master.
NOTE:
•
During an IRF merge, the switches of the IRF fabric that fails the master election must reboot to re-join the
IRF fabric that wins the election. The reboot can be automatically performed or must be manually
performed depends on the switch model.
• After a master election, all slave member switches initialize and reboot with the configuration on the
master, and their original configuration, even if has been saved, will be lost.
IRF fabric management and maintenance
After the IRF fabric is established, you can access the master from any member switch to manage all the
resources of the member switches.
Member ID
An IRF fabric uses member IDs to uniquely identify and manage its members. Member IDs are used in
interface numbering and file management:
• In interface numbering—Assume an interface on the switch that operates in standalone mode was
named GigabitEthernet 3/0/1. After the switch joined an IRF fabric, it receives a member ID of 2,
and the name of the interface changes to GigabitEthernet 2/3/0/1.
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