This specifies whether a given hop in an explicit path is strict(1) -- the LSP must go directly to this hop from the previous one with no intermediate router -- or loose(2) -- other routers may be traversed in between, with the signaling protocol filling in the details. This distinction directly affects how rigidly the network enforces the intended route: an all-strict path guarantees an exact topology but can fail to signal if any listed hop becomes unreachable, while loose hops give RSVP-TE more flexibility to route around problems. A tunnel that repeatedly fails to establish along a strict-hop path but succeeds when that hop is changed to loose suggests the strict adjacency itself has become invalid, for example because a link was removed.