Maintaining the T4000 Host Subsystem

For optimum router performance, verify the condition of the Routing Engines and the control boards.

Each host subsystem comprises a Routing Engine and an adjacent control board functioning together. To maintain the host subsystem:

Check the host subsystem LEDs (HOST0 and HOST1) on the craft interface. During normal operations:
- The green host subsystem OK LED on the craft interface is lit.
- The red host subsystem FAIL LED on the craft interface is not lit.
  If the red HOST0 FAIL or HOST1 FAIL LED is lit, see Troubleshooting the T4000 Host Subsystems
Check the LEDs on the control board. See Maintaining the T4000 Control Boards.
Check the LEDs on the Routing Engine. See Maintaining the T4000 Routing Engines