Abstract: A network traffic monitoring system includes a router, a terminal adaptor, a digital service unit, a frame relay/leased network, a traffic monitoring apparatus, and a monitor. A subscriber line is connected to the router. The terminal adaptor interfaces the router to the network side. The digital service unit is connected to the terminal adaptor through an I interface. The frame relay/leased network is made up of at least one of a higher-speed relay router and a switching unit and transmission lines. The traffic monitoring apparatus monitors the internet traffic on a physical line between the terminal adaptor and the digital service unit. The monitor controls the traffic monitoring means to start and stop totalization processing, sets a subnet mask for determining a totalization unit, and acquires traffic information as a totalization result from the traffic monitoring apparatus.

Abstract: For enabling automatic restoration of a path in a transmission network including a plurality of crossconnect systems and a plurality of communication routes, a unit specifying circuit specifies, as a first and a second specified unit, two of the crossconnect systems in accordance with a particular route which is selected as the path. It will be assumed that a failure occurs in a particular point of the path. In this event, the first specified unit executes a predetermined operation in cooperation with the second specified unit. When the predetermined operation finishes, each of the crossconnect systems is operable to select, as the path, another one of the communication routes. It is preferable that the failure is detected in accordance with a path alarm indication signal which is surely supplied from the particular point to each of the first and the second specified units.