Data relay device, delivery route management system, delivery route management system and delivery path management method

摘要

PROBLEM TO BE SOLVED: To reduce packet loss of multicast data accompanying transfer of a client device by suppressing increase of a communication cost.;SOLUTION: A data repeater 30 informs a multicast path management device 20 of a fact that there is a subscription request when the subscription request in a multicast group from the client device 50 is received. The multicast path management device 20 generates a list of base station devices 40 which are subordinates of the data repeater 30, generates a list of adjacent base station devices 40 adjacent to the respective base station devices 40 of the list and creates a list of adjacent data repeaters 30 having the adjacent base stations 40 in their subordinates. The multicast path management device 20 instruct the respective adjacent data repeaters 30 to construct a multicast tree beforehand and delay time until construction of the multicast tree accompanying the transfer of the client device 50 is suppressed by a fact that the multicast tree is constructed beforehand as instructed.;COPYRIGHT: (C)2005,JPO&NCIPI