BlackDiamond 8800 and BlackDiamond X Series Switches

Each ExtremeXOS image comes bundled with an I/O module image and contains a unique upgrade compatibility version number, known as the I/O version number.

This number determines the relationship between the I/O module image and the ExtremeXOS image and their support for hitless upgrade. The I/O version number contains build information for each version of ExtremeXOS, including the major and minor version numbers, and the I/O version number.

Extreme Networks generates the I/O version number, and this number increases over time. Any modifications to the I/O module image after a major software release changes the I/O version number. For example, if Extreme Networks delivers a patch or service release that modifies the I/O module image, the I/O version number increases.

When you initiate a hitless upgrade by using the run msm-failover {force} command on the backup MSM, it checks the I/O version number to determine if a hitless upgrade is possible.

Depending on the currently running software, the switch performs, allows, or denies a hitless upgrade. The following describes the switch behavior: