According to my knowledge, Tunnel - Path between Ingress and Egress Routers.Used for Traffic Engineering (Band-width assigned) LSP Path - Path between Ingress and Egress Routers.Used for MPLS.

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LSP is Predetermined path Over two Label edge Routers. It is established over Label switching router. It is based on Forwarding equivalence class. LSP is required to MPLS forwarding.

MPLS Traffic Engineering build unidirectional Tunnel between source and destination. IT is based on LSP Path.

For more details cisco


According to my understanding of Cisco terminology:

Tunnel: what you configure in the router, it is keyword used by Cisco to indicate the interface. For ex: I will configure a tunnel between Router1 and Router2.

LSP: is somehow virtual, means if you combine the labels between R1 and R2 and put them in top of each other. You will get an LSP. It is the virtual path that can be visualized by the stack of labels.

To clear it further, a tunnel can have a primary and a secondary path between the same R1 and R1. But usually each of the paths will have a different LSP (labels).


Tunnel is a construct/container of following: source, destination, path/s. It is the tunnel that is used by upper level application to resolve NH to destinations. e.g. L3-vpn, L2-vpn.

Source = Sender, destination = receiver, path = LSP. Tunnel may have more that one path or LSP. Use-case of multiple path is primary/secondary

LSP may be signaled by control protocols like LDP, RSVP or Segment-routing (even BGP labeled unicast).

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