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Debugging and Diagnostics
This chapter describes debugging and diagnostics for the MXL switch.

Offline Diagnostics

The offline diagnostics test suite is useful for isolating faults and debugging hardware.
The diagnostics tests are grouped into three levels:
•Level 0 — Level 0 diagnostics check for the presence of various components and perform essential
path verifications. In addition, Level 0 diagnostics verify the identification registers of the components
on the board.
•Level 1 — A smaller set of diagnostic tests. Level 1 diagnostics perform status, self-test, access, and
read-write tests for all the components on the board and test their registers for appropriate values. In
addition, Level 1 diagnostics perform extensive tests on memory devices (for example, SDRAM, flash,
NVRAM, EEPROM) wherever possible.
•Level 2 — The full set of diagnostic tests. Level 2 diagnostics are used primarily for on-board MAC
level, Physical level, external Loopback tests, and more extensive component diagnostics. Various
components on the board are put into Loopback mode and test packets are transmitted through
those components. These diagnostics also perform snake tests using virtual local area network (VLAN)
configurations.
NOTE: Diagnostic is not allowed in Stacking mode, including member stacking. Avoid stacking
before executing the diagnostic tests in the chassis.
Important Points to Remember
• You can only perform offline diagnostics on an offline standalone unit. You cannot perform
diagnostics if the ports are configured in a stacking group. Remove the port(s) from the stacking
group before executing the diagnostic test.
• Diagnostics only test connectivity, not the entire data path.
• Diagnostic results are stored on the flash of the unit on which you performed the diagnostics.
• When offline diagnostics are complete, the unit or stack member reboots automatically.

Running Offline Diagnostics

To run offline diagnostics, use the following commands.
For more information, refer to the examples following the steps.
1. Place the unit in the offline state.
EXEC Privilege mode
offline stack-unit <id>
296 Debugging and Diagnostics