Packet routing with redundant network devices

An environment includes at least two network devices and a plurality of downstream devices or networks. The downstream devices or networks are communicatively coupled to network interfaces of the network devices using a plurality of data cables. The data cables each comprise a switch device configured to switch communication paths to the coupled network devices. Each of the data cables communicatively couple each of the network devices to one of the plurality of downstream devices or networks so that each of the downstream devices or networks has a communications path to each of the network devices and a switchable communications path from each of the network devices. The network devices do not arbitrate active/passive status via direct communication. Based on data contained in a reply packet indicating that a request packet sent by the first network device was acknowledged, the first network device determines that the first network device is an active network device.