What is the most secure router protocol?

Could you elaborate on what you mean by the "most secure router protocol"? Is there a specific type of router or network environment you're interested in? In general, router security is a multifaceted issue that involves factors such as encryption protocols, firewall settings, and regular software updates. Some protocols, such as OpenVPN or IKEv2, are known for their strong encryption and security features, but the most secure protocol for a given situation will depend on a variety of factors. It's important to conduct a thorough assessment of your network's security needs and vulnerabilities before selecting a router protocol.