【单选题】In a circuit-switched network, if each link has n circuits, for each link used by the end-to-end connection, the connection gets ( ) of the link's bandwidth for the duration of the connection.
【简答题】The four circles are apart from each other.Link their centers to form. a quadrilateral, then the total are a of the shaded parts in the figure is( ). (A)2π (B)4π (C)6π (D)8π