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IRF uses a strict configuration file synchronization mechanism to ensure that devices in an IRF can
work as a single device on the network, and to ensure that after the master fails, the other devices can
operate normally.
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When a slave starts up, it automatically finds out the master, synchronizes the master's
configuration file, and executes the configuration file; if all devices in an IRF start up
simultaneously, the slaves synchronize the master's initial configuration file and execute it.
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When the IRF operates normally, all your configurations will be recorded into the current
configuration file of the master, and are synchronized to each device in the IRF; when you save
the current configuration file of the master as the initial configuration file by using the
save
command, all slaves execute the same saving operation to make the initial configuration files of all
devices consistent.
Through the real-time synchronization, all devices in the IRF keep the same configuration file. If the
master fails, all the other devices can execute various functions according to the same configuration
file.
2) Configuration file application
The configuration file can be divided into two parts: global configuration and port configuration. When a
slave applies these two kinds of configurations of the master, it deals with them in different ways:
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Global configuration: All slaves execute the current global configuration on the master exactly,
that is, all members in the IRF apply the same global configuration.
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Port configuration: When a slave applies the port configuration on the master, it cares about the
configuration related to its own port, for example, the slave with the member ID of 3 only cares
about the configuration related to the GigabitEthernet 3/0/x port on the master. If there is a
configuration related to its own port, it will apply the configuration; if not, no matter what
configuration has been made to the port before the slave joins the IRF, the slave will function
using null-configuration.
IRF maintenance
In an IRF, direct neighbors exchange hello packets periodically (the period is 200 ms). Without
receiving any hello packet from a direct neighbor for ten periods, a member considers that the hello
packets timed out, and the IRF isolates the expired device in the topology and updates its topology
database.
When an IRF port of a member becomes down, the member broadcasts the information to all the other
members immediately. If the IRF port of the master is down, an election is triggered.
IRF Configuration Task List
Before configuring an IRF, you need to define the roles and functions of all the members for better
planning. Because the configuration of some parameters takes effect after device reboot, you are
recommended to first configure parameters, power off the devices, connect devices physically, power
on the devices, and finally the devices will join in the IRF automatically. After an IRF is formed, you can
configure and manage the IRF by logging in to any device in the IRF. The operations you make take
effect on the master, and will be applied to the member devices in the IRF. For easy fault location and
device maintenance, the Switch 4510G provides slave view, where you can execute the
display
,
terminal
, and
debug
commands.
