What defines a routable address in networking?

A routable address in networking is fundamentally an IP address that can be reached over the internet, meaning it is publicly accessible. This is typically designated as a global unicast address, which can be used to identify devices on the internet without any need for intermediary systems or address translation to access the wider network. This type of address ensures that data packets can traverse different networks and reach their intended destinations.

In contrast, addresses that are confined to local networks or are part of private network spaces, such as those used in home or enterprise setups, are considered non-routable. These types of addresses cannot be directly accessed from the internet without a form of Network Address Translation (NAT) to facilitate communication. The distinction is crucial for understanding how devices communicate across different networks, particularly when addressing the need for global connectivity versus internal network operations.