Section: Automation and Programmability

The next hop is 10.0.0.1 because it has a better administrative distance. Router D has possible routing information through different protocols. When routes to the same prefix compete, the router chooses the route with the lowest administrative distance before comparing protocol-specific metrics. In the exhibit, the EIGRP path via 10.0.0.1 is preferred over the OSPF-learned alternative because EIGRP has a better administrative distance than OSPF. The next hop is therefore 10.0.0.1. Cisco CCNA 200-301 v1.1 IP Connectivity expects engineers to separate administrative distance from metric: administrative distance ranks route sources, while the metric ranks paths within the same routing protocol. The corrected answer is the 10.0.0.1 next hop because it has the better administrative distance.

In a traditional "Router-on-a-Stick" configuration, a router uses subinterfaces to route traffic between different VLANs. Each subinterface acts as the default gateway for a specific VLAN.
However, a Layer 3 switch (also known as a Multilayer Switch) can perform this same inter-VLAN routing internally using SVIs (Switch Virtual Interfaces). When you upgrade to a Layer 3 switch, you no longer need the external router and its subinterfaces to move traffic between VLANs.