UNADDRESSED DEVICE COMMUNICATION FROM WITHIN AN MPLS NETWORK

An unaddressed device installed inline in a path of an MPLS network can communicate a packet from within the MPLS network to an upstream device without knowledge of the necessary MPLS labeling by sending the packet intentionally in the wrong direction: downstream. To communicate to an upstream device, the unaddressed device sends a packet downstream into the MPLS network on the opposite side and through the opposite outgoing port from that which would be used for a packet sent to the same device in a non-MPLS network. This behavior forces the MPLS network, when it next inspects the packet, to re-label it with the correct labeling to route the packet on a path back upstream to the recipient device. In this manner, the MPLS architecture is used to redirect or loop back packets from an unaddressed inline device to the upstream device.