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Limited Operation Mode and
Minimal Operation Mode
This appendix describes two switch operational modes wherein switch behavior is restricted to protect
the stability of the switch and network and to allow troubleshooting or corrective action. The two
switch operational modes are limited operation mode and minimal operation mode. They result from
different failure conditions, but respond to similar procedures for troubleshooting and correcting their
respective failure conditions.
This appendix contains the following sections:
• Limited Operation Mode on page 111
• Minimal Operation Mode on page 112
Limited Operation Mode
A switch enters limited operation mode after a catastrophic reboot. As the switch boots, it checks to see
whether a catastrophe caused this reboot. If that is the case, the switch enters limited operation mode.
In this context, a catastrophe is defined as:
• When diagnostics fail on an Alpine or Summit switch;
• When diagnostics fail when run on an MSM in a BlackDiamond that has only a single MSM;
• When a hardware device/component fails and triggers a system "panic" event;
• When the POST fails.
NOTE
Running diagnostics on an Alpine or Summit switch causes the switch to reboot twice: once to clear the
state of the switch, again after the diagnostics have run, to make the switch available for use. The
decision whether to enter limited operation mode is made before the second boot occurs.
In effect, limited mode "stunts" the bring-up process so that ports are not enabled, many system tasks
are not spawned, and I/O modules are not powered up.
In limited operation mode, only the CPU, NVRAM, management port, console port, a limited set of
system tasks, and a limited subset of CLI commands are active.
Advanced System Diagnostics and Troubleshooting Guide
111
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Troubleshooting
