This paper proposes a Highly-Available Open Shortest Path First (HA-OSPF) router which consists of two OSPF router modules-active and standby-to support a highavailability network. Each router module runs a Linux operating system, high-availability management middleware (HAM middleware), and OSPF daemon. The HAM middleware consists of an Availability Management Framework (AMF) service, checkpoint service, interface monitor, OSPF fault manager, and fault handler; it provides a health check, state information exchange, and takeover mechanism. The experimental results are given to show the system availability of the HA-OSPF router on a PC-based prototype system. Furthermore, to build a carrier grade commercial product, we realize a HA-OSPF router on an industry standard compliant Advanced Telecom Computing Architecture (ATCA) hardware platform. From actual measurements, we show that our PC-based and ATCA-based HA-OSPF routers take only 166 and 131 ms to switch over to a standby router module when there is a software fault and 360 and 331 ms with a hardware failure respectively.