This object holds the label value this router expects to see on frames arriving from the upstream hop in order to match them to this specific static transit tunnel entry, as the description states. It must be configured to exactly match what the upstream router was configured to push toward this router, since a mismatch means arriving frames simply won't be recognized as belonging to this transit LSP at all. For example, an incoming-label value of 100024 must match precisely what the upstream ingress or transit router pushes, so this router can correctly match and then swap it for the configured outgoing label.