In ISNS for Alcatel OS 9700 switches, software failover is implemented by using which components?

• A. A single CMM with redundant power
• B. A pair of storage arrays
• C. Two fully operational CMM modules
• D. A backup ROM image

Answer: (C)

Software failover is achieved by having a redundant control plane. Two fully operational CMM modules provide this, because they run the management and ISNS-related software and stay synchronized so the second module can take over immediately if the first fails. This keeps sessions, state, and management continuity intact, minimizing disruption to services.

Other options don’t provide runtime control-plane redundancy. A single CMM with redundant power protects mainly against power loss but not a failure of the control module itself. A pair of storage arrays focuses on data storage resilience, not the switch’s software control. A backup ROM image helps after a corruption or hardware failure but cannot actively take over ongoing operations in real time.