 It then forwards the packet along to the next router in the path, which swaps the packet's outer label for another label, and forwards it to the next router.The last router in the path removes the label from the packet and forwards the packet based on the header of its next layer, for example IPv4.Due to the forwarding of packets through an LSP being opaque to higher network layers, an LSP is also sometimes referred to as an MPLS tunnel.