This indicates whether a given hop in an explicit path is strict (must be a direct, single IGP hop from the previous address) or loose (may be reached via any number of intermediate routers), and like the hop address itself it cannot be changed once created. An admin sets loose hops when they only care about forcing traffic through a particular region or router without pinning every intermediate link, which matters when the underlying topology between two loose hops might itself change. For example, a path defined as hop1=strict, hop2=loose lets the LSP take any IGP-preferred route to reach hop2 as long as it goes directly from the router to hop1 first.