H3C Technologies H3C S12500 Series Switches - Manual (Page 13)

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When devices form an IRF fabric, they elect a master to manage the IRF fabric, and all other devices back
up the master. When the master device fails, the other devices elect a new master automatically. For more
information about master election, see "
Master election ."
MPU roles
Each IRF member device has one or two MPUs, which play different roles, as follows:
Role Description
Global active MPU
Active MPU of the master device. You configure and manage the
entire IRF fabric at the CLI of the global active MPU.
Local active MPU
Active MPU that manages the local device. This MPU has the
following responsibilities:
• Manages the local device, including synchronizing
configuration between the local active MPU and the local
standby MPU, processing protocol packets, and creating and
maintaining route entries.
• Handles IRF related events, such as master election and
topology collection.
Standby MPU
For the global active MPU, all other MPUs, including local active
MPUs, are global standby MPUs.
If a member device has two MPUs, the one backing up the local
MPU is the local standby MPU from the perspective of the member
device.
IRF member ID
An IRF fabric uses member IDs to uniquely identify and manage its members. This member ID information
is included as the first part of interface numbers and file paths to uniquely identify interfaces and files in
an IRF fabric. For example, after you assign a device with member ID 2 to an IRF fabric, the name of
interface GigabitEthernet 3/0/1 changes to GigabitEthernet 2/3/0/1, and the file path
slot1#flash:/test.cfg changes to chassis2#slot1#flash:/test.cfg.
If two devices have the same IRF member ID, they cannot form an IRF fabric. If the IRF member ID of a
device has been used in an IRF fabric, the device cannot join the fabric.
By default, the standby MPU is automatically assigned the same ID as the active MPU. You can change
the standby MPU ID of a member device to quickly recover IRF configuration for a device that has only
one MPU as described in " Fast-restoring IRF configuration for a one-MPU member ."
IRF port
An IRF port is a logical interface for the connection between IRF member devices. Each IRF-capable
device supports two IRF ports.
In standalone mode, the IRF ports are named IRF-port 1 and IRF-port 2.
In IRF mode, the IRF ports are named IRF-port n/1 and IRF-port n/2, where n is the member ID of the
device. The two IRF ports are referred to as "IRF-port 1" and "IRF-port 2" in this book for simplicity.