Juniper Networks MX240 manual Replacing an SCB, Master in the Current state field

Chapter 13: Replacing Hardware Components

1.Determine whether the host subsystem is functioning as the master or as the backup, using one of the two following methods:

■Check the Routing Engine LEDs on the craft interface. If the green RE MASTER LED is lit, the corresponding host subsystem is functioning as the master.

■Issue the following command. The master Routing Engine is designated

Master in the Current state field:

user@host> show chassis routing-engine

Routing Engine status:
Slot 0:
Current state	Master
...

2.If the host subsystem is functioning as the master, switch it to backup using the command:

user@host> request chassis routing-engine master switch

3.On the console or other management device connected to the Routing Engine that is paired with the SCB you are removing, enter CLI operational mode and issue the following command. The command shuts down the Routing Engine cleanly, so its state information is preserved:

user@host> request system halt

Wait until a message appears on the console confirming that the operating system has halted.

For more information about the command, see the JUNOS System Basics and

Services Command Reference.

NOTE: The SCB might continue forwarding traffic for approximately 5 minutes after the request system halt command has been issued.

Replacing an SCB

The router can have up to two SCBs. They are located in the front of the chassis in the slots marked 0 and 1/0 (the multifunction slot1/0 can contain either SCB1 or DPC0). With a Routing Engine installed, each SCB weighs approximately

9.6 lb (4.4 kg).

The SCBs are hot-pluggable. If the router contains a redundant host subsystem, the backup SCB and Routing Engine are hot-removable and hot-insertable. Before you replace an SCB or a Routing Engine, you must take the host subsystem offline (see

Replacing Host Subsystem Components ■ 97