2010 International Conference on P2P, Parallel, Grid, Cloud and Internet Computing (3PGCIC), pp , 作者： Yoh Shiraishi, Ryo Miki 指導教授：許子衡 教授 報告學生：馬敏修

 Introduction  Proposed Method ◦ Assumed Environments ◦ Method Overview ◦ Algorithms  Exchanging information with adjacent nodes  Advertising a multicast session  Joining/remaining in a multicast group  Leaving from a multicast group  Sending data packets  Evaluation ◦ Experimental Settings ◦ Experimental Results  Conclusion

 Geocasting cannot continuously deliver information to multicast members if these members move outside the GR.  To solve this, we developed a geocast-based multicast method that continuously manages a member node that has passed through the geocast region as a group member even if that member moves outside the region.

 This service specifies a region in which a multicast sender wants to advertise a multicast session and sends the channel information.  A user passes through multiple advertisement regions and acquires channel information from multiple senders.  The user selects one of these channels to watch, and join the multicast group of the corresponding sender at any time from anywhere.

 To realize the above service, our proposed method needs to satisfy two requirements: 1) A node can receive a session advertisement once it enters the advertisement region. 2) A node that has the session information about a certain multicast group can join and leave the group at any time.

 This proposed method uses five algorithms to manage multicast members: 1) Exchanging information with adjacent nodes. 2) Advertising a multicast session. 3) Joining/remaining in a multicast group. 4) Leaving from a multicast group. 5) Sending data packets.

 All nodes in a network periodically send a hello packet to exchange ID and location information with adjacent nodes.  By this processing, each node manages the information of the adjacent nodes that it can directly communicate with.

 A multicast sender sends an advertisement packet to 1) advertise a multicast session 2) construct (cache) a routing path to the sender  We develop a geocast-based algorithm that uses adjacent node information exchanged by using Hello packets.

 The steps of this algorithm are as follows. a) Generating an Advertisement packet and specifying an advertisement region (AR). b) Specifying a forwarding node and sending an Advertisement packet. c) Receiving an Advertisement packet. d) Forwarding an advertisement packet.

 A node that accepts an advertisement packet in the AR periodically sends a join/keep packet to the multicast sender as long as it remains in the multicast group.  A join/keep packet is sent to the multicast sender using the ID of the sender described in the Advertisement packet and the coordinates of the center of the AR.

 There are three steps for sending a join/keep packet: a) Generating a join/keep packet. b) Forwarding a join/keep packet. c) Receiving a join/keep packet.

 Leaving a node from a multicast group is realized by eliminating the node’s entry from the member table when either one of the following conditions is satisfied. 1) The multicast sender receives a Leave packet from the multicast member. 2) The information of the member is not updated and the life of the member expires.

 As the algorithms for sending data packets, we implemented three routing protocols: a) Location-guided k-ary b) Location-guided Steiner c) ODMRP

 LGK is an algorithm for constructing k-ary multicast trees based on the location information of multicast members.

 LGS uses a Steiner tree as a multicast tree.  We use the following steps to approximate the Steiner tree. 1) The approximate algorithm adds the multicast members to a remaining member list. 2) It selects a member from the member list to make up the edge with the minimum distance to the multicast sender. 3) It deletes the member selected in step (2) from the member list.

 LGS delivers data packets based on the edge information constructed by the above steps.

 ODMRP defines a set of nodes responsible for forwarding packets.  The node set is called a forwarding group (FG).

 A continuous multicast model for MANET environments was developed.  In this model, a node that was in a certain region in the past can join, remain in, or leave a multicast group for that region at any time.  The proposed method requires hello packets but does not require flooding in any of the multicast processes from advertising a multicast session to sending data packets.  Consequently, our method has high scalability for larger networks and more multicast senders.