When the TTL policy above is set to fixed, this is the actual TTL value imposed on the MPLS label for every packet entering this static tunnel, regardless of the original packet's own TTL. An admin sets this high enough (e.g. 255) that legitimate long-haul traffic never gets dropped mid-tunnel from TTL exhaustion, since a too-low fixed value would silently drop packets that would otherwise have survived plenty of hops. For example, a fixed TTL of 64 on a tunnel spanning six core hops leaves ample margin, whereas a fixed TTL of 4 on that same path would cause packets to expire and be dropped before ever reaching the tail-end.