Abstract: Networking between two host devices can leverage a converged high-speed input/output fabric (“HSIO”) technology (e.g., Thunderbolt). HSIO networking can be implemented between two host devices as a “cross-domain” service. Each host device can establish a data transmit path segment to an endpoint at the boundary of its HSIO domain. A host device can send a login request to another host device and can respond to a login request from another host device by establishing a data receive path segment that connects to the endpoint location of the data transmit segment of the requesting host device. When both devices have sent and responded to login requests, a bidirectional cross-domain data transport is established and can be used to communicate network data. The HSIO networking service can present a virtual Ethernet controller interface to other software on the host device.