Underlay network formation

An apparatus comprising:

• one or more network interfaces to communicate with a network;
• a processor coupled to the network interfaces and configured to execute one or more processes;
• and
• a memory configured to store a process executable by the processor, the process when executed configured to:
• designate a particular networking device among a set of networking devices as a seed device and one or more interfaces of the seed device as discovery interfaces;
• coordinate, starting from the one or more discovery interfaces of the seed device, discovery of a Layer 2 topology of the set of networking devices, by designating one or more interfaces of a discovered networking device as discovery interfaces;
• and
• convert, starting from at least one of the network devices farthest from the seed device in the Layer 2 topology and ending with the seed device, links of the Layer 2 topology into Layer 3 links, to form an underlay network.

A tangible, non-transitory, computer-readable medium storing program instructions that cause a supervisory service to execute a process comprising:

• designating, by the service, a particular networking device among a set of networking devices as a seed device and one or more interfaces of the seed device as discovery interfaces;
• coordinating, by the service and starting from the one or more discovery interfaces of the seed device, discovery of a Layer 2 topology of the set of networking devices, by designating one or more interfaces of a discovered networking device as discovery interfaces;
• and
• converting, by the service and starting from at least one of the network devices farthest from the seed device in the Layer 2 topology and ending with the seed device, links of the Layer 2 topology into Layer 3 links, to form an underlay network.