Abstract: A multicast processing section constructs, when it is determined that a received packet is a packet on a multicast packet and multicast group management protocol, a table showing a correlation between a host device and a multicast group in a port number-multicast physical address correlation storing section as well as in a multicast router-connected port storing section according to the received packet, and controls to transfer a packet for each multicast group between a multicast router and host devices according to the table.

Abstract: A communication device connectable to an IP network includes a congestion monitor unit monitoring whether the communication device is congested, and a congestion information creating unit creating congestion information concerning a congested state of the communication device when the congestion monitor unit detects the congested state thereof, the congestion information being sent to other devices connected to the IP network.

Abstract: In a wireless LAN system chiefly using a millimeter wave, a satellite station is provided with an active phased planar-array antenna, the radiating directivity characteristic of which can be freely changed. When a master station receives a control frame transmitted from the satellite station prior to the commencement of normal communication, the master station transmits a carrier wave. The satellite station determines such a directivity characteristic of an antenna as to receive this carrier wave with the strongest intensity, and fixes the characteristic. Thus, an optimal communication environment can be secured. When the number of errors in a received data frame or the receiving electric field intensity received by the satellite station in normal communication is inferior to a respective predetermined threshold, the deterioration of the communication environment can be coped with by determining again.

Abstract: In a wireless LAN system chiefly using a millimeter wave, a satellite station is provided with an active phased planar-array antenna, the radiating directivity characteristic of which can be freely changed. When a master station receives a control frame transmitted from the satellite station prior to the commencement of normal communication, the master station transmits a carrier wave. The satellite station determines such a directivity characteristic of an antenna as to receive this carrier wave with the strongest intensity, and fixes the characteristic. Thus, an optimal communication environment can be secured. When the number of errors in a received data frame or the receiving electric field intensity received by the satellite station in normal communication is inferior to a respective predetermined threshold, the deterioration of the communication environment can be coped with by determining again.

Abstract: A mobile user station periodically searches for a connectable access point and stores the address of a connectable access point that has been found in a master-station management table. When the mobile user station moves from one cell to another under these conditions, the state of communication with the old access point deteriorates. When the state of communication with the old access point deteriorates to such a degree that it becomes necessary for the mobile user station to connect to a new access point, the mobile user station sends a connection request to the access point stored in the master-station management table and performs communication via the new access point. As a result, when connection to a new access point becomes necessary owing to movement of the mobile user station between cells, the changeover between access points can be performed quickly without searching for an access point.

Abstract: A fixing roll used for electrophotography in which a fluoro resin layer having a surface roughness Rz of not greater than 3.5 .mu.m, gloss of not greater than 50% and an angle of contact with water of not less than 115.degree. is coated on outer surface of the roll. The fixing roll is manufactured by a method which comprises coating a fluoro resin paint to the surface of a core thereby forming coating layer, applying smoothing fabrication to the surface of the coating layer and, subsequently, applying heat treatment to form a fused fluoro resin layer.

Abstract: Disclosed is a rotary ring for spinning machinery, such as ring spinning machines and ring twisting macines, which provides stabilized rotation of a ring-shaped rotator and involves no end breakage of yarn during spinning. This is accomplished by specifying the coefficient of friction .mu. between the ring-shaped rotator and the ring-shaped supporter, the relation between the weight W of the ring-shaped rotator and the outside diameter D.sub.1 and ring-shaped top flange inside diameter D.sub.2, and the relation between the width A along the radial direction and the height H along the axial directio between the sliding surfaces of the ring-shaped rotator and the ring-shaped supporter. This rotary ring makes it possible to realize higher spindle speed and higher productivity of yarn.