Configuration Synchronization Mechanism; Master Election; Irf Multi-Active Detection; Multi-Active Handling Procedure - HP 5900 Series Configuration Manual

Configuration synchronization mechanism

IRF uses a strict running-configuration synchronization mechanism so all chassis in an IRF fabric can work
as a single node, and after the master fails, other members can operate normally.
In an IRF fabric, all chassis get and run the running configuration of the master. Any configuration you
have made is propagated to all members.
For more information about configuration management, see Fundamentals Configuration Guide.

Master election

Master election is held each time the IRF fabric topology changes, for example, when the IRF fabric is
established, the master device fails or is removed, the IRF fabric splits, or IRF fabrics merge. Adding new
member devices or the merge of an Active IRF fabric and a Recovery IRF fabric does not trigger master
election.
Master election uses the following rules in descending order:
Current master, even if a new member has higher priority.
1.
When an IRF fabric is being formed, all members consider themselves as the master, and this rule
is skipped.
Member with higher priority.
2.
Member with the longest system uptime.
3.
Two members are considered starting up at the same time if the difference between their startup
times is equal to or less than 10 minutes. For these members, the next tiebreaker applies.
Member with the lowest bridge MAC address.
4.
The IRF fabric is formed on election of the master.
During an IRF merge, the members of the IRF fabric that fail the master election will automatically reboot
to rejoin the IRF fabric that wins the election.
After a master election, all subordinate members reboot with the configuration on the master, and their
original configuration, even if it has been saved, is removed.

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 device's MAD implementation detects active IRF fabrics with the same Layer 3 global configuration
by extending the LACP, BFD, ARP, or IPv6 ND protocol.
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