A mechanism for efficiently distributing multicast messages having group destination addresses to subscribing entities in a computer network. The network includes a plurality of virtual local area network (VLAN) designations among those entities and a multicast network device (MND) configured to generate at least one unique multicast (MVLAN) identifier (ID) for each group destination address. Each MVLAN ID encompasses all VLAN designations of the subscribing entities, except for the VLAN designation associated with the entity sourcing the message. Each MVLAN ID is propagated to intermediate devices of the network and attached to subsequent multicast messages to enable efficient distribution of those messages over the network.
A plurality of terminals communicate. One terminal belongs to a plurality of groups of terminals. In the communication apparatus, a terminal information memory stores terminal identifiers. A sending section sends the communication information with the terminal identifiers of other terminals participating in one group to the other terminals. A receiving section receives information sent by the other terminal. A group discrimination section compares the received terminal identifiers with the stored terminal identifiers, and discriminates the group from which the received information was communicated according to the comparison.
The invention relates to a network interface apparatus called a router or the like which is provided in a network system and relays the transmission of a data packet as a bundle of information. In order to know the permission or inhibition of communication of the data packet at a high speed while suppressing an increase in memory capacity, there is provided a coupling management table in which one VLAN ID is allocated to each terminal (each MAC address) and coupling information showing whether the communication from the terminal having a transmitting side VLAN ID to the terminal having a receiving side VLAN ID is permitted (logic "1") or inhibited (logic "0") has been stored at each of the coordinate points using the VLAN ID on the transmitting side and the VLAN ID on the receiving side as coordinates.
A system, device, and method for reducing multicast forwarding states in a multicast communication system maintains forwarding states in such a way that the non-default forwarding states have non-overlapping source address ranges. Each forwarding state is associated with a source address range encompassing one or more source addresses. When a non-default forwarding state is installed, the source address range for the forwarding state is selected so that the source address range does not overlap with the source address ranges of any other non-default forwarding states. The source address range for a particular forwarding state may be adjusted as new routes are learned or existing routes are changed or aged.
A method and apparatus for filtering data packets in a shared-medium or point-to-multipoint communications network. A filter unit is sent a data packet carrying a filter tag value in a packet addressed to the filter unit. The value is stored in the filter unit and subsequently received packets not addressed to the filter unit itself are forwarded only if they carry the stored filter tag. An embodiment of particular interest applies the method to Ethemet frames over a telecommunications access network (including optical or wireless networks), and uses the VLAN tag field to carry the filter tag information.
