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Troubleshoot I2C errors on the NetIron XMR/MLX

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TitleTroubleshoot I2C errors on the NetIron XMR/MLX

Inthe XMR/MLX and MLX-e systems, system status is obtained periodically by the Management Module (MM) by polling other modules through a system-wide I2C bus.The I2C bus is a two-wire (Clock and Data) interface allowing the master device (in this case, the MM) to individually address multiple devices residing on the bus.In these systems, multiple I2C buses are routed on the backplane and used for communications between the MM and the line cards, SFMs, fan FRUs, and power supplies.Error monitoring in the application firmware is responsible for identifying problems in the I2C path, and setting alerts as necessary.

Beginning with Softwarerelease version 4.1, when an I2C failure occurs on a management module, a set of static and dynamic syslog messages are generated in the output of the show logging command. A syslog message is also sent to the SNMP log server. A description of these messagesid described in the NetIron XMRHardware Installation Manual and the NetIron MLXHardware Installation Manual.

Software Release: All NetIron Ironware software releases
Fixed in Version: N/A

A particular component such as a rearfan, power supply orfan tray may be holding the bus causing an I2Clockup. Once this component is removed from the chassis the I2C bus will be freed and the console messages will stop being seen on the console.


The syslog messages logged by the Internal monitoring feature in 4.1 and later releases will identify which component in the parenthesis that is causing the I2C bus lockup from the System log entries.

System: i2c recovered (GIEI = clear), Severity Minor, Mux index 0, Mux tap 4, ID 0xe, Addr 0x0, (FANTRAY1)
System: bad i2c access (GIEI = set), Severity Major, Mux index 0, Mux tap 4, ID 0xe, Addr 0x0, (FANTRAY1)

If the console output is also displaying mux_channel errors then reseat the following device that is displayed in the parenthesis in order to clear the I2C lockup. If the problem returns for the same device, request an RMA from Brocade Technical Support.

Additional notes



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