For each TE LSP, subLSP, or LDP LSP instance that the MPLS Topology Server creates, the MPLS Topology Server also creates the LSPHop instances along the path of the LSP. It starts with the source LSP segment for the LSP and uses the nextHopKey value in the LSP table manager to create the LSPHops from the LSP source to the LSP destination, hop by hop.
If an LSPHop is the first one for an LSP, the MPLS Topology Server creates the Source relationship between that LSPHop and the source device for the LSP. If an LSPHop is the last one for an LSP, the MPLS Topology Server creates the Destination relationship between that LSPHop and the destination device for the LSP.
Here are some other relationships that are computed for LSPHops:
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LSPHop relationship LayeredOver
Points from an LSPHop to the network connection that is underlying the LSPHop.
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LSPHop relationship Underlying
Points from an LSPHop to the LSP to which the LSPHop belongs.
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LSPHop relationship NextHop
Points from an LSPHop to the next LSPHop along the path of an LSP. This relationship is computed only for an LSPHop that is not the last hop in the path of an LSP.
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LSPHop relationship PreviousHop
Points from an LSPHop to the previous LSPHop along the path of an LSP. This relationship is computed only for an LSPHop that is not the first hop in the path of an LSP.