H3C Technologies H3C S7500E Series Switches - Manual (Page 15)

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Therefore, to make the IRF virtual device operate normally, you need to make sure that the link state is
normal and connect the IRF ports of two devices correctly before configuring an IRF virtual device; after
the establishment of the IRF virtual device, configure necessary anti-attack policies to ensure device
safety.
Recovery of an IRF virtual device after IRF partition
If two member devices of an IRF virtual device cannot communicate with each other due to link failure,
the IRF virtual device is divided into two independent IRF virtual devices, each of which has only one
member device. Then, you need to repair the IRF link. After IRF link recovery, both of the two IRF virtual
devices prompt you that an IRF virtual device merge will happen, and then you can reboot one of the
two member devices to complete the merge. Then, the rebooted device joins the IRF virtual device
whose member device is not rebooted as the slave.
IRF Multi-Active Detection Mechanism
A link disconnection causes an IRF virtual device to divide into two IRF virtual devices that operate with
the same global configuration. Because these IRF virtual devices cause address collision, network
failure probably extends. To address this problem, the multi-active detection (MAD) mechanism is
introduced. The MAD mechanism detects the presence of multiple identical IRF virtual devices and
handles the problem to decrease the influences to services caused by IRF virtual device partition. The
MAD mechanism provides the following functions:
z Detection: Enabled for an IRF virtual device, the MAD mechanism detects the network for multiple
active IRF virtual devices with the same global configuration. This is done with the Link
Aggregation Control Protocol (LACP), and the Bidirectional Forwarding Detection (BFD) protocol.
z Collision handling: When an IRF virtual device is partitioned, if multiple identical active IRF virtual
devices are detected, the MAD mechanism keeps only the one with the lowest master ID to operate
normally (keeping the active state). The state of all the other IRF virtual devices is set to recovery
(disabled) and all physical ports (usually the ports for forwarding data traffic) are shut down except
for the reserved ones to make sure that these IRF virtual devices cannot forward data traffic.
z Failure recovery: The MAD mechanism prompts you for multi-active collision, and the device then
tries to repair the failed IRF links . If the reparation fails, you need to manually repair the failed links.
To make the partitioned IRF virtual devices merge again after the links are repaired, manually
restart the recovery IRF virtual device, and then it restores to the active state, and all disabled ports
come up to forward traffic.