transport tunnel

Routers are connected to physical links that are used to carry traffic. When a service is set up using MPLS, transport LSP tunnels are set up between Provider Edge routers. Each service or customer sends traffic through a service tunnel within the transport LSP tunnel. Transport tunnel LSPs are identified by MPLS labels that are swapped at each intermediate NE, or transit LSR, along the LSP from the ingress to the egress of the MPLS network.