A fiber installed in a "U" configuration has two end points that a cable may hook to. When making a measurement, it is useful to be able to say which end was hooked to the input from the instrument box. In order to do this, the fiber ends must be identified. The identifier is a name, along with a description to further aid the interpreter in determining which end was used as the input A name, unique within the context of the well, for an instrument box cable to hook to. Any description of the node that may be useful in identifying the hookup. Unique identifier for the end point.