Cisco Catalyst 3550

Chapter3 Troubleshooting
Understanding POST Results
3-2
Catalyst 3550 Multilayer Switch Hardware Installation Guide
78-11358-01
Understanding POST Results
Table 3-1 lists the eight POST tests and their associated LEDs.
POST tests run automatically each time the switch is powered on. When the
switch begins POST, the port LEDs turn amber for 2 seconds, and then they turn
green. The System LED flashes green, and the RPS LED turns off. As each test
runs, the port LEDs, starting with number 1, turn off. The remaining port LEDs
each turn off in sequence as the system completes a test.
When POST completes successfully, the port LEDs return to the status mode
display, indicating that the switch is operational. If a test fails, the port LED
associated with the test turns amber, and the system LED turns amber.
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
LED 1 DRAM
LED 2 Flash memory
LED 3 CPU interface buffer
LED 4 CPU interface ASIC
LED 5 Switch core ASIC
LED 6 TCAM
LED 7 Ethernet controller ASIC
LED 8 Ethernet interfaces