Configuration Guide User guide
326 FastIron Configuration Guide
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More about IronStack technology
IronStack topologies
Brocade IronStack technology supports both linear and ring stack topologies. Because the unicast
switching follows the shortest path in a ring topology, this topology offers the strongest redundancy.
When the ring is broken, the stack recalculates the forwarding path the resumes the flow of traffic
within a few seconds. In a ring topology, all stack members must have two stacking ports, however,
In a linear topology, both end units use only one stacking port, leaving the other port available as a
data port. To see an illustrated example of each topology, refer to “Brocade IronStack topologies”
on page 239.
Port down and aging
If a unit is powered down, or the stacking link is removed, the system immediately detects the port
down and knows that its neighbor is gone. That unit is immediately removed from the Active
Controller. If a unit is gone or no longer stack-enabled, but its stacking link is still on, it will take 20
seconds to age the neighbor out. The following message will be logged and displayed.
Warning! my mac=00f0.424f.4243, age out up-stream
Brocade IronStack device roles and elections
There are three distinct roles played by units that are part of an IronStack:
• Active Controller
• Standby Controller
• Stack member
Active Controller
The Active Controller contains the saved and running configuration files for each stack member.
The configuration files include the system-level settings for the stack, and the interface-level
settings for each stack member, as well as MIB counters and port status. The Standby Controller
also has a synchronized copy of the Active Controller startup config file for use in the event the
Active Controller fails.
When a stack is formed, the console function for each stack member is automatically redirected to
the Active Controller console. The Active Controller console port handles all stack management
functions, as well as ping, Telnet sessions, and tftp image downloads for every stack member. If
you connect to the console port on a stack member that is not the Active Controller, you are
automatically directed through the console of the Active Controller.
The Active Controller synchronizes its start-up configuration with the Standby Controller and the
rest of the stack members. You can recover the previous flash configuration of the Standby
Controller and the stack members by issuing the stack unconfigure command. For an example of
this command and the output generated, refer to “Unconfiguring an IronStack” on page 287.
The Active Controller may reset the rest of the stack members, if necessary. However, if the Active
Controller itself must be reset because of a role or ID change, you must issue the reset command.