Presentation on theme: "Impact Analysis of Cheating in Application Level Multicast s １０９０１７６ Masayuki Higuchi."— Presentation transcript:
Impact Analysis of Cheating in Application Level Multicast s １０９０１７６ Masayuki Higuchi
Purpose Application level multicast is efficient communication technology, and it is used in peer-to-peer service, but they have problems. To evaluate performance of Application- Level Multicast.
IP multicast Consist of multicast routers, and the router control packets, but all router must be multicast router, so infrastructure building is difficult. It is unreliable because of the best-effort communication by IP layer. packet
Application Level multicast A technique whereby hosts or end-nodes are organized into an overlay distribution tree without requiring any specific support from the network. physical network overlay network
HBM protocol A Host Based Multicast protocol Control of a single host, the rendezvous point (RP) or controller. Periodically, each group member measures its distance to others. The RP is then responsible for the overlay topology calculation and its dissemination among the group members. RP new member
P2P streaming service Sharecast Without high performance server. User’s nodes relay streaming data How to connect. Send IP address, MAC address, and channel ID, and version to administrator. Response access point.
How to cheat Always reports a distance of 5 to the source. Adds 10 seconds to the RTT distances it measured to any other group member. Also, delays by 10 seconds any measurement probes if receives from any other group member. root 5 +10 cheat-node
Performance measures for Application level multicast The link stress Defined as the number of redundant copies of a data packet on the network link. The relative delay penalty (RDP) Defined as the ratio *TD/*UD. *TD is the tree delay. *UD is the unicast delay. UD TD
Impact of cheating in worst case cheating 2 2 2 2 2 2 The link stress: 5 The maximum RDP: 2/2 The link stress: 1 The maximum RDP: 14/2 3 3 3 3 cheat-node
Impact of cheating in general The link stress: 6 The maximum RDP: 11/7 The link stress: 3 The maximum RDP: 9/7 5 cheating 33 cheat-node
Countermeasures against Cheating Users receives the data from two or more nodes. As a result the influence of the switch of the connection can be decreased. To detect the cheating, transmit ping to the router that connect one hop short of the cheat-node, and compare with RTT that cheat-node returned. cheat-node real value cheated value
Conclusion and Future Works The countermeasures is effective measures in theory. As a future work, through simulations, confirm the effectiveness of them.