Patent ID: 6950431

Claim:
A network relay apparatus for connecting networks to each other, which are logically constructed, comprising: a reception port; a transmission port; and relay means for relaying a multicast packet between logically constructed networks based upon reception information containing reception port information related to a reception port which receives the multicast packet, and reception source network information related to a first network functioning as a reception source of said multicast packet; and also transmission information provided in correspondence with said reception information and containing transmission port information related to a port through which said multicast packet is transmitted, and transmission source network information related to a second network functioning as a transmission destination of said multicast packet, wherein said reception information contains life information of a received multicast packet; and one of first life information and second information is registered into said life information, as a result of a comparison made between said first life information which has already been registered in said life information and said second life information owned by a newly received multicast packet.