Juniper Networks M160 manual Maintaining the PCGs, 135

Maintaining Hardware Components

The following guidelines apply specifically to fiber-optic cable:

When you unplug a fiber-optic cable from a PIC, always place a rubber safety plug over the transceiver on the PIC faceplate and on the end of the cable.

Anchor fiber-optic cable to avoid stress on the connectors. When attaching fiber to a PIC, be sure to secure the fiber so it is not supporting its own weight as it hangs to the floor. Never let fiber-optic cable hang free from the connector.

Avoid bending fiber-optic cable beyond its bend radius. An arc smaller than a few inches can damage the cable and cause problems that are difficult to diagnose.

Frequent plugging and unplugging of fiber-optic cable into and out of optical instruments, such as ATM or SONET/SDH analyzers, can cause damage to the instruments that is expensive to repair. Instead, attach a short fiber extension to the optical equipment. Any wear and tear due to frequent plugging and unplugging is then absorbed by the short fiber extension, which is easy and inexpensive to replace.

Keep fiber-optic cable connections clean. Small micro-deposits of oil and dust in the canal of the transceiver or cable connector could cause loss of light, reducing signal power and possibly causing intermittent problems with the optical connection.

To clean the transceivers, use an appropriate fiber-cleaning device, such as RIFOCS Fiber Optic Adaptor Cleaning Wands (part number 946). Follow the directions for the cleaning kit you use.

After you have cleaned the transceiver on the fiber-optic PIC, make sure that the connector tip of the fiber-optic cable is clean. Use only an approved alcohol-free fiber-optic cable cleaning kit, such as the Opptex Cletop-S® Fiber Cleaner. Follow the directions for the cleaning kit you use.

Maintaining the PCGs

The router has two Packet Forwarding Engine Clock Generators (PCGs) installed in the slots labeled PCG 0 and PCG 1 on the rear of the chassis, as shown in Figure 3. To maintain the PCGs, perform the following procedures regularly:

Check the LEDs on the PCG faceplates. The green LED labeled OK lights steadily when the PCG is functioning normally. The blue LED labeled MASTER lights steadily on the master PCG. For more information, see “PCG Components” on page 19.

Issue the CLI show chassis environment pcg command to check the status of the PCGs. As shown in the sample output, the master PCG is designated Online - Master clock and the standby PCG Online - Standby:

user@host> show chassis environment pcg

PCG 0 status:

Maintaining Packet Forwarding Engine Components 135