Irf Multi-Active Detection; Multi-Active Handling Procedure - HP 10500 Series Configuration Manual

During an IRF merge, the devices of the IRF fabric that fails the master election must reboot to rejoin the
IRF fabric that wins the election. The reboot can be performed automatically or manually, depending on
the configuration. See
After a master election, all subordinate devices reboot with the configuration on the master. The
configuration files of the subordinate members are still retained, but these files do not take effect in the
IRF fabric. A subordinate member reboots with its own startup configuration file only when it is converted
to the standalone mode.

IRF multi-active detection

An IRF link failure causes an IRF fabric to split in two IRF fabrics operating with the same Layer 3
configurations, including the same IP address. To avoid IP address collision and network problems, IRF
uses multi-active detection (MAD) mechanisms to detect the presence of multiple identical IRF fabrics,
handle collisions, and recover from faults.

Multi-active handling procedure

The multi-active handling procedure includes detection, collision handling, and failure recovery.
Detection
The MAD implementation of this device detects active IRF fabrics with the same Layer 3 global
configuration by extending the LACP or BFD protocol.
These MAD mechanisms identify each IRF fabric with a domain ID and an active ID (the member ID of
the master). If multiple active IDs are detected in a domain, MAD determines that an IRF collision or split
has occurred.
IMPORTANT:
LACP MAD handles collisions in a different way than BFD MAD. To avoid conflicts, do not enable LACP
MAD together with BFD MAD.
For a comparison of these MAD mechanisms, see
Collision handling
MAD mechanisms remove multi-active collisions by setting one IRF fabric to the Detect state and other IRF
fabrics to the Recovery state. The Detect-state IRF fabric is active. The Recovery-state IRF fabric is inactive.
Only members in the Detect-state fabric can continue to forward traffic.
LACP MAD handles a multi-active collision in the following process:
1. Compares the number of members in each fabric.
2. Sets the fabric that has the most members to the Detect state and all other fabrics to the Recovery
state.
3. If all IRF fabrics have the same number of members, compares the member IDs of their masters.
4. Sets the IRF fabric that has the lowest numbered master to the Detect state and all other fabrics to
the Recovery (disabled) state.
5. Shuts down all physical network ports in the Recovery-state fabrics except their physical IRF ports
and any ports you have specified with the mad exclude interface command.
"Enabling IRF auto merge."
"Configuring MAD."
7