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Maintain Breakout Cables

Breakout cables have one transceiver preattached to one end and more than one transceiver preattached to the other end. You can use the cables to channelize a port and increase the number of interfaces. For example, you can channelize the QSFP28 ports on the rear panel of EX4400 switches by connecting breakout cables and by using CLI configuration when those ports are configured as network ports (see Port Settings).

Disconnect a Breakout Cable

Before you disconnect a breakout cable from a device, ensure that you have taken the necessary precautions for safe handling of laser (see Laser and LED Safety Guidelines and Warnings).

Ensure that you have the following parts and tools available:

  • An antistatic bag or an antistatic mat to store the cable, if you are disconnecting the cable from all the ports it is connected to

  • Rubber safety caps to cover the ports on the device, or a replacement cable

  • Rubber safety caps to cover the transceivers at the ends of the cable

  • An electrostatic discharge (ESD) grounding strap—not provided

To disconnect a breakout cable:

  1. Disable the port to which the cable is connected by issuing the following command:
  2. Place the antistatic bag or antistatic mat on a flat, stable surface if you are disconnecting the cable from all the devices it is connected to.
  3. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to a site ESD point.
  4. Label the cable so that you can reconnect it correctly.
    CAUTION:

    Do not leave the transceivers at the ends of the cable uncovered except when connecting or disconnecting the cable. The rubber safety cap keeps the transceivers clean and protected.

    Do not bend the cables beyond their minimum bend radius. An arc smaller than a few inches in diameter can damage the cables and cause problems that are difficult to diagnose.

    Do not let the cables hang free from the connector. Do not allow fastened loops of cables to dangle, which stresses the cables at the fastening point.

  5. By using your fingers, pull the tab on the transceiver attached to the cable to disengage it (see Figure 1).
    Figure 1: Disconnect a Breakout CableDisconnect a Breakout Cable
      1
    —

    Tab to pull the transceiver

      3
    —

    Port at the other end

      2
    —

    Channelized port on a device

    		 
  6. Grasp the transceiver and gently slide it approximately 0.5 in. (1.3 cm) straight out of the port.
    CAUTION:

    To prevent ESD damage to the transceiver, do not touch the connector pins at the end of the transceiver.

  7. By using your fingers, grasp the body of the transceiver and pull it straight out of the port.
  8. Cover the transceiver with a rubber safety cap.
  9. Secure the cable so that it does not support its own weight as it hangs to the floor. If there is a cable management system, arrange the cable in the cable management system to prevent it from dislodging or developing stress points. Place excess cable out of the way in a neatly coiled loop in the cable management system. Placing fasteners on the loop helps to maintain its shape.
  10. If you are disconnecting the cable from all the devices it is connected to, place the cable in the antistatic bag or on the antistatic mat placed on a flat, stable surface.

The procedure to disconnect other types of breakout cables is the same as the procedure described in this topic.

Connect a Breakout Cable

CAUTION:

To prevent ESD damage to the transceiver, do not touch the connector pins at the end of the transceiver.

If you are connecting an active optic breakout cable to a device, ensure that you have taken the necessary precautions for safe handling of laser (see Laser and LED Safety Guidelines and Warnings).

Ensure that you have an electrostatic discharge (ESD) grounding strap (not provided).

Note:

After you connect a cable or after you change the media-type configuration, wait for 6 seconds for the interface to display operational commands.

Note:

We recommend that you use only cables purchased from Juniper Networks with your Juniper Networks device.

CAUTION:

If you face a problem running a Juniper Networks device that uses a third-party optic or cable, the Juniper Networks Technical Assistance Center (JTAC) can help you diagnose the source of the problem. Your JTAC engineer might recommend that you check the third-party optic or cable and potentially replace it with an equivalent Juniper Networks optic or cable that is qualified for the device.

To connect a breakout cable:

  1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to a site ESD point.
  2. Remove the cable from its bag.
    CAUTION:

    Do not leave the transceivers at the ends of the cable uncovered except when connecting or disconnecting the cable. The rubber safety cap keeps the transceivers clean and protected.

  3. If the transceiver attached to the cable is covered with a rubber safety cap, remove the cap. Save the cap.
  4. If the port on the device is covered with a rubber safety cap, remove the cap. Save the cap. If you are hot-swapping a cable, wait for at least 10 seconds after removing the cable from the port before installing a new cable.
    CAUTION:

    Before you slide the transceiver into the port, ensure that the transceiver is aligned correctly. Misalignment might cause the pins to bend, making the cable unusable.

    Do not bend the cables beyond their minimum bend radius. An arc smaller than a few inches in diameter can damage the cables and cause problems that are difficult to diagnose.

    Do not let the cables hang free from the connector. Do not allow fastened loops of cables to dangle, which stresses the cables at the fastening point.

  5. By using both hands, carefully insert the transceiver in the empty port. The connectors must face the chassis. Slide the transceiver in gently until it is fully seated (see Figure 2).
    Figure 2: Connect a Breakout CableConnect a Breakout Cable
      1
    —

    Transceiver

      3
    —

    Ports at the other end

      2
    —

    Channelized port on a device

    		 
  6. Repeat Step 5 for all ports to which the cable must be connected.
  7. Secure the cable so that it does not support its own weight as it hangs to the floor. If there is a cable management system, arrange the cable in the cable management system to prevent the cable from dislodging or developing stress points. Place excess cable out of the way in a neatly coiled loop in the cable management system. Placing fasteners on the loop helps to maintain its shape.

The procedure to connect other types of breakout cables is the same as the procedure described in this topic.