Patent ID: 7661025

Claim:
A method, comprising: processing network traffic for logical connections established between network devices using a first processor; maintaining physical layer connectivity information for the established logical connections using a second processor; receiving a request to perform an asymmetric in-service software upgrade, wherein the asymmetric in-service software upgrade request is configured to, if accepted, cause the second processor to maintain the physical layer connectivity information for the established logical connections while running a first internetwork operating system that is different than a second internetwork operating system concurrently used by the first processor; prior to performing the requested asymmetric in-service software upgrade, determining a command set for said second internetwork operating system, wherein said command set comprises a listing of a plurality of configuration commands; for each of said plurality of configuration commands, performing a syntax check on said second processor and said first internetwork operating system, said syntax check identifying internetwork operating system commands that are present in the command set of the second internetwork operating system but absent from a command set of the first internetwork operating system; generating a Mismatched Command List (MCL) having entries for each of the identified internetwork operating system commands; and performing the requested asymmetric in-service software upgrade according to an analysis of the MCL, wherein said first processor and said second processor are configured to operate in a Stateful SwitchOver mode of operation, wherein said first processor is configured to be an Active processor and said second processor is configured to be a Standby processor, and wherein if said MCL is not empty, said Standby processor is prevented from reaching a hot-standby state.