Perform A Swap Test

Note: Although steps to remove and install an HCM are provided here, ensure that you refer to the appropriate hardware guide for the latest information. Before performing a swap test, always check for bent pins in the midplane and check the HCM for stuck pins in the connector. Pins stuck in the component connector can damage other good slots during a swap test.

The HCM is hot-pluggable. You can perform a swap test on an HCM to pinpoint the problem.

1. Remove an HCM
2. Install an HCM

Remove an HCM

The HCM is hot-pluggable. You can perform a swap test on an HCM to try to pinpoint the problem

To remove an HCM:

1. Place an electrostatic bag or antistatic mat on a flat, stable surface.
2. If a Routing Engine is installed in the same row as the HCM you are removing, remove the Routing Engine first. If two Routing Engines are installed, use one of the following two methods to determine which HCM is functioning as master:
   • Note which of the blue MASTER LEDs is lit on the Routing Engine faceplates.
   • Use the following command:
     user@host> show chassis environment hcm

     HCM 0 status:
     			State 															Online Master
     			FPGA Revision 												27
     		  HCM 1 status:
     				State 														Online Standby
     				FPGA Revision 											27

     The master HCM is designated Master in the State field.

3. If you are removing the master Routing Engine and a second Routing Engine is installed, issue the following command to switch mastership to the standby host module:
   user@host>request chassis routing-engine master switch

   warning: Traffic will be interrupted while the PFE is re-initialized
   Toggle mastership between routing engines ? [yes,no] (no) yes
   
   Resolving mastership...

   If the Routing Engines are running Junos OS Release 6.0 or later and are configured for graceful switchover, the standby Routing Engine immediately assumes Routing Engine functions and there is no interruption to packet forwarding. Otherwise, packet forwarding halts while the standby Routing Engine becomes the master and the Packet Forwarding Engine components reset and connect to the new master Routing Engine. For information about configuring graceful switchover, see the section about Routing Engine redundancy in the Junos OS System Basics Configuration Guide.

   Note: Router performance might change if the standby Routing Engine’s configuration differs from the former master’s configuration. For the most predictable performance, configure the two Routing Engines identically, except for parameters unique to a Routing Engine, such as the hostname defined at the [edit system] hierarchy level and the management interface (fxp0 or equivalent) defined at the [edit interfaces] hierarchy level. To configure Routing Engine-specific parameters and still use the same configuration on both Routing Engines, include the appropriate configuration statements under the re0 and re1 statements at the [edit groups] hierarchy level and use the apply-groups statement. For instructions, see the Junos OS System Basics Configuration Guide.

4. On the console or other management device connected to the Routing Engine, enter CLI operational mode and use the following command to shut down the router software cleanly and preserve Routing Engine state information:

   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 OS System Basics Configuration Guide.

   Note: The router might continue forwarding traffic for a few minutes after the request system halt command has been issued.

5. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
6. Loosen the thumbscrews located at each end of the Routing Engine faceplate, using a Phillips screwdriver if necessary.
7. Grasp the handle and slide the unit about halfway out of the chassis.

   Caution: Slide the Routing Engine straight out of the chassis. Damage can result if it gets lodged because of uneven movement.

8. Place one hand under the Routing Engine to support it, slide it completely out of the chassis, and place it on the antistatic mat or in the electrostatic bag.
9. Grasp the handle of the HCM and slide the unit about halfway out of the chassis.

   Caution: Slide the HCM straight out of the chassis. Damage can result if it gets lodged because of uneven movement.

10. Place one hand under the HCM to support it, slide it completely out of the chassis, and place it on the antistatic mat or in the electrostatic bag.

Install an HCM

To install an HCM:

1. Attach an ESD grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
2. Place one hand under the HCM to support it and grasp the handle on the faceplate with the other hand.
3. Align the rear of the HCM with the guide rails inside the chassis and slide it in completely.

   Caution: Align the HCM carefully with the guide rails and push it in evenly. Damage can result if it gets lodged in the rails because of uneven movement.

4. Place one hand under the Routing Engine to support it and grasp the handle on the faceplate with the other hand.
5. Align the rear of the Routing Engine with the guide rails inside the chassis and slide it in completely.

   Caution: Align the Routing Engine carefully with the guide rails and push it in evenly. Damage can result if it gets lodged in the rails because of uneven movement.

6. Tighten the thumbscrews on the Routing Engine faceplate to secure the Routing Engine.
7. Use the show chassis environment hcm command to verify that the HCM is functioning correctly.