ALMにおける予備の接続先を用いた安定したツリーの構築法の提案

摘要

ALM（Application Layer Multicast）では，エンドホスト間のユニキャストにより，マルチキャストの配信を行うため,マルチキャストツリー内の中継ノードが，離脱すると，マルチキャストツリーの下位ノードへの配信の中断が発生する.本稿では,すべてのノードに,予め予備の接続先を設定し，親ノードの離脱後に，子ノードが予備の接続先に接続することで．配信の中断を防ぐ中断のない安定したALMツリー構築法を捷案する．%ALM (Application Layer Multicast) constructs multicast delivery tree among end hosts. Each host end in the multicast tree delivers streaming data by uncast along the constructed multicast tree. In ALM, when non-leaf nodes leave the multicast tree, all nodes belonged to the sub-tree, where the left node play the roll of root for the sub-tree, cannot receive streaming data. In this paper, in order to cope with this problem, we propose a resilient ALM tree construction algorithm, where a spare space is pre-assigned for each node. In our proposed algorithm, when a parent node leaves the multicast tree, the children nodes are connected to their spare spaces instantly and resume receiving the streaming data. Due to this mechanism, our proposed method prevents intermission of receiving streaming data. In this paper, we present the resilient multicast tree construction algorithm using pre-assigned spare space.