Recovering from a Software Failure

Recov er ing from a Software Failure

If the system does not boot, does not accept new software, or has corrupted software or configurations, you can use the test switch on the module in slot 0 to allow you to reboot and download new software. When you download new software to slot 0, the system overwrites the software on all other modules. If a card in another slot is malfunctioning, you can use its switch to erase its software, after which the card downloads the software from slot 0.

Caution Contact technical support before using the test switch. The test switch can erase your software and configuration files, which can result in a loss of service and unrecoverable configurations.

Refer to Table B-1 for number descriptions, and set the switch to a number using a small flat-blade screwdriver in the arrow slot:

Figure B-1: Test Switch

Table B-1: Test Sw itch Actions

Switch Setting Description

0

Normal operation

1

Do not use

2

Do not use

3

Boots a limited OS where you can set the IP address and download a new software version. This setting does not erase the OS or configuration files. For example:

1. Set the switch to 3 and restart.

2. Attach a console directly and set the IP address using the following command:

setip address mask [gateway]

3. Set the switch back to 0.

4. TFTP new software according to "Installing the Software and Configuration."

  After downloading, the system restarts using the new software.

4

Do not use

5

Erases the OS and configuration in Flash memory. For example:

1. Set the switch to 5 and restart.

2. Attach a console directly and set the IP address using the following command:

setip address mask [gateway]

3. Set the switch back to 0.

4. TFTP new software according to "Installing the Software and Configuration."

  After downloading, the system restarts using the new software.

6

Erases the configuration in Flash memory. The system uses the default settings in the OS. For example:

1. Set the switch to 6 and restart.

2. Set the switch back to 0 and restart.

7

Do not use

8

Boots only to the command line so you can edit the configuration. The concentrator does not load the configuration, so the concentrator does not have any network connectivity. However, if your configuration is crashing the system, this switch allows you to make changes to the configuration. For example:

1. Set the switch to 8 and restart.

2. Set the switch back to 0.

3. Edit the configuration file normally and enter save.

  The system reboots normally.

9

Allows the letmein password for 5 minutes after every startup. For security purposes, you should limit access to the chassis to authorized personnel only. You can leave the setting at 9 permanently; it is the same as setting 0 except for the letmein password 5 minutes after startup. Your normal passwords also work during the initial 5 minutes.

Switch Setting	Description
0	Normal operation
1	Do not use
2	Do not use
3	Boots a limited OS where you can set the IP address and download a new software version. This setting does not erase the OS or configuration files. For example: 1. Set the switch to 3 and restart. 2. Attach a console directly and set the IP address using the following command: setip address mask [gateway] 3. Set the switch back to 0. 4. TFTP new software according to "Installing the Software and Configuration." After downloading, the system restarts using the new software.
4	Do not use
5	Erases the OS and configuration in Flash memory. For example: 1. Set the switch to 5 and restart. 2. Attach a console directly and set the IP address using the following command: setip address mask [gateway] 3. Set the switch back to 0. 4. TFTP new software according to "Installing the Software and Configuration." After downloading, the system restarts using the new software.
6	Erases the configuration in Flash memory. The system uses the default settings in the OS. For example: 1. Set the switch to 6 and restart. 2. Set the switch back to 0 and restart.
7	Do not use
8	Boots only to the command line so you can edit the configuration. The concentrator does not load the configuration, so the concentrator does not have any network connectivity. However, if your configuration is crashing the system, this switch allows you to make changes to the configuration. For example: 1. Set the switch to 8 and restart. 2. Set the switch back to 0. 3. Edit the configuration file normally and enter save. The system reboots normally.
9	Allows the letmein password for 5 minutes after every startup. For security purposes, you should limit access to the chassis to authorized personnel only. You can leave the setting at 9 permanently; it is the same as setting 0 except for the letmein password 5 minutes after startup. Your normal passwords also work during the initial 5 minutes.

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