User isolation between network devices

An apparatus comprising:

• a processor;
• a plurality of network interfaces coupled to a first computer network that includes an aggregation device and configured as network-to-network interfaces (NNIs);
• one or more network interfaces coupled to user devices and configured as user-to-network interfaces (UNIs);
• and
• a memory configured to store one or more software processes, the one or more software processes when executed by the processor operable to:
• select one or more NNIs of the plurality of NNIs to forward traffic from the apparatus to the aggregation device,
• designate one or more NNIs of the plurality of NNIs that have not been selected to forward traffic from the apparatus to the aggregation device as network-to-network interface alternates (NNI-ALTs), and
• treat the one or more NNI-ALTs as UNIs for user data traffic forwarding decisions.

A non-transitory computer-readable media having software encoded thereon, the software when executed operable to:

• identify a plurality of network interfaces of a network device that are configured to communicate with other network devices in a first computer network as network-to-network interfaces (NNIs);
• identify one or more network interfaces of the network device that are configured to provide access to the first computer network to user devices as user-to-network interfaces (UNIs);
• select one or more NNIs of the plurality of NNIs to forward traffic from the network device to an aggregation device of the first network that couples the first computer network to a second computer network;
• designate one or more NNIs of the plurality of NNIs that have not been selected to forward traffic from the device to the aggregation device as network-to-network interface alternates (NNI-ALTs);
• and
• is treat the one or more NNI-ALTs as UNIs for user data traffic forwarding decisions.