US Patent 11281453 Methods and systems for a hitless rollback mechanism during software upgrade of a network appliance

A network appliance running a first firmware may roll back to that first firmware in a hitless manner during an unsuccessful upgrade to a second firmware. Before the attempted upgrade, a first process in the first firmware is providing a service. The upgrade process is initiated to upgrade the network appliance from the first firmware to a second firmware. The upgrade process can include stopping communication via a data plane of the network appliance to the first process, and detecting an upgrade failure. The upgrade process is hitless because rolling back the upgrade process occurs without halting the first firmware. Rolling back the upgrade includes restoring communications via the data plane to the first process.