Abstract: A multi-layered film made of sequentially stacked first dielectric layer, recording layer, record-assist layer, second dielectric layer and first reflection layer on a disc substrate having a concavo-convex structure at least on one surface thereof. An ultraviolet-setting resin layer is formed to cover the multi-layered film. The record-assist layer is controlled in thickness to satisfy the relation d/4<a<3d, or more preferably the relation d/2?a?2d, between the thickness d of the recording layer and the thickness a of the record-assist layer. The stacking order of the multi-layered film may be opposite. In this case, a light-transmitting sheet is provided to cover the multi-layered film via a bonding layer.

Abstract: A multi-layered film made of sequentially stacked first dielectric layer, recording layer, record-assist layer, second dielectric layer and first reflection layer on a disc substrate having a concavo-convex structure at least on one surface thereof. An ultraviolet-setting resin layer is formed to cover the multi-layered film. The record-assist layer is controlled in thickness to satisfy the relation d/4<a<3d, or more preferably the relation d/2?a?2d, between the thickness d of the recording layer and the thickness a of the record-assist layer. The stacking order of the multi-layered film may be opposite. In this case, a light-transmitting sheet is provided to cover the multi-layered film via a bonding layer.

Abstract: A communication network capable of establishing an SVC bypass route when a failure occurs in a PVC multiplexed line wherein each of ATM switches at both ends of a PVC stores the relations of SVC specifying information and the other party PVC information in association with each PVC in a management table. At the time of bypassing, one of the switches transmits a message including the other party PVC information to another ATM switch for each PVC to be bypassed and another ATM switch specifies a PVC to be switched on the basis of the received message and switches the PVC to an SVC specified by the corresponding SVC specifying information stored in the management table.