Refer to the exhibit. A customer requires maximum uptime for the data plane between R1 and R3 running OSPF. Which solution must the design include for high availability if the routing process on R2…

Nonstop Forwarding (NSF) typically applies to routers with redundant control planes (e.g., redundant supervisors), allowing the standby control plane to take over without data plane interruption during a failure, which is not the same as a single process restart on a single router for maintenance.

Graceful Restart allows a router (R2) to restart its OSPF routing process without its neighbors (R1 and R3) detecting a topology change or tearing down adjacencies. During the restart, R1 and R3 continue to forward data traffic to R2 using their existing forwarding information, maintaining data plane connectivity until R2's routing process fully recovers and re-establishes OSPF adjacencies. This minimizes service disruption during maintenance.

Nonstop Forwarding (NSF) on R1 and R3 would not directly address the scenario of R2's routing process requiring maintenance; NSF is primarily for control plane redundancy within a single device or for graceful control plane failure detection, not for process restarts on a transit router.

BFD (Bidirectional Forwarding Detection) is a rapid fault detection protocol for data paths, used to quickly detect link or neighbor failures, but it does not maintain data plane forwarding during a routing protocol process restart.