How does call fallback work?

How does call fallback work?

• A. It lowers call quality when network congestion occurs.
• B. It forwards all calls to voicemail on failure.
• C. It always uses the same alternate path regardless of availability.
• D. Routing logic selects an alternate path if primary call control is unreachable.

Answer: (D)

Call fallback is about resiliency in signaling. If the primary call-control path becomes unreachable—due to a server outage, network failure, or signaling transport issue—the system’s routing logic automatically switches to an alternate path to continue control of the call. This means selecting a backup call-control server or a different signaling route so the call setup and management can proceed without dropping the call. It’s driven by availability, not by lowering quality, and it isn’t tied to a single fixed alternate path; the choice can change based on what is reachable at the moment.

Call fallback is about resiliency in signaling. If the primary call-control path becomes unreachable—due to a server outage, network failure, or signaling transport issue—the system’s routing logic automatically switches to an alternate path to continue control of the call. This means selecting a backup call-control server or a different signaling route so the call setup and management can proceed without dropping the call. It’s driven by availability, not by lowering quality, and it isn’t tied to a single fixed alternate path; the choice can change based on what is reachable at the moment.