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Troubleshooting Tip: FortiSwitch logging 'bcm-iproc-i2c 18008000.i2c: transaction timed out' errors

Description

This article describes troubleshooting steps for a FortiSwitch issue where repeated crash logs are generated with the message:

bcm-iproc-i2c 18008000.i2c: transaction timed out.

Scope

FortiSwitch.

Solution

The FortiSwitch is displaying the following crash log entries and is unable to detect the connected SFP modules:

4085: 1970-01-01 03:51:10 bcm-iproc-i2c 18008000.i2c: transaction timed out

4086: 1970-01-01 03:51:12 bcm-iproc-i2c 18008000.i2c: transaction timed out

...

4095: 1970-01-01 03:51:41 bcm-iproc-i2c 18008000.i2c: transaction timed out

Additionally, running the command get switch modules summary shows all SFP ports as EMPTY, indicating no modules are recognized:

Portname State Type DMI Transceiver RX Vendor Part Number Serial Number

--------- ------ ----- --- ----------- --- ------- ------------ --------------

port13 EMPTY

port14 EMPTY

...

port30 EMPTY

Resolution:
This issue is often caused by the use of unsupported third-party SFP modules. To resolve the issue:

Ensure that only Fortinet-approved SFP modules are connected to the switch.
Confirm the FortiSwitch is running the latest supported FortiSwitch OS firmware.

Refer to the following link for a list of supported SFP modules:

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