Techniques are described for providing high availability for a network device, e.g., a router, using full memory replication between a primary virtual machine (VM) and a standby VM running on the network device. In one example, the techniques provide hot-standby high availability for a router by initializing a primary VM and a standby VM on the router at the same time. In another example, the techniques provide high availability for the router by initializing a standby VM on the router upon detecting a failure of the primary VM. In both examples, the primary VM controls the routing functionality and periodically stores a full memory state. Upon a failure of the primary VM, a hypervisor may perform a full memory replication between the primary VM and the standby VM. The standby VM may then take control of the routing functionality at the last stored state of the memory.