Abstract: A physical interconnect having multiple virtual paths is coupled between network devices of independent networks operated by different entities. In one aspect, the interconnect is monitored so that the entities can simultaneously and separately monitor network traffic being exchanged across the interconnect. Each entity can be assigned two virtual paths through the interconnect to pass network traffic through their network device, over the interconnect, through a network device of the other entity, back over the interconnect link and back through their network device. The network devices can be configured to loop back network packets using a variety of loopback configurations. Hardware policers that monitor capacity usage of the virtual paths can also be tested.