Chapter 3 Troubleshooting
Understanding POST Results
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Catalyst 2900 Series XL Hardware Installation Guide
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Understanding POST Results
Each time the switch is powered on, eight POSTs run automatically to check the
most important system components before the switch begins forwarding packets.
When the switch begins its POST, the port status LEDs turn amber for 2 seconds,
and then they turn green. As each test runs, the port status LEDs turn off, starting
with number 1x. The port status LEDs for ports 2x to 8x each turn off in turn as
the system completes a test.
When the POST completes successfully, the port status LEDs go off, indicating
that the switch is operational. If a test fails, the port status LED associated with
the test turns amber, and the system LED turns amber. Table 3-1 lists the eight
POST tests and their associated LEDs.
Note POST failures are usually fatal. Call Cisco Systems if your switch does not
pass POST.
Table 3-1 POST Test Descriptions
Switch LED Component Tested
1DRAM
2 Flash memory
3SwitchCPU
4 System board
5 CPU interface ASIC
6SwitchcoreASIC
7 Ethernet controller
ASIC
8 Ethernet interfaces
