In addition to static and dynamic routing, what is the third type of indirect routing?

The third type of indirect routing is default routing. Default routing serves as a simplified mechanism for packets that do not have a specific routing path defined in the routing table. This approach allows a router to send packets to a designated "next hop" or gateway when the destination address does not match any entry in the routing table.

Default routing is particularly useful in networks with a limited number of known paths, enabling efficient data handling without the need for an extensive routing table. This makes it a practical option for scenarios such as connecting to the internet from a local network, where the router can send all traffic not explicitly addressed elsewhere to a broader network or service provider.

While static routing and dynamic routing are both well-defined methods of managing routing paths, default routing specifically acts as a catch-all that simplifies routing decision-making when specific routes are not available.

The other options mention routing concepts but do not represent the indirect routing category accurately in the context of this question. Static and dynamic routing cover the processes used to define and manage routing paths, while algorithmic routing doesn't conform to the traditional classifications of routing methods.