The present invention aims to prevent damages of a magnetic tape in a magnetic tape cassette adapted to be operated in a recording and reproducing apparatus which can similarly operate a plurality of magnetic tape cassettes. In an embodiment, network flow information for a network flow between a first endpoint and a second endpoint is received from a network device interposed between the first endpoint and the second endpoint, wherein the network flow information includes at least an address for the first endpoint and a particular payload identification number. A third portion of the optical fibers between the first and second portions extends between the first and second substrates.