Cancellation Algorithm Based On The Pim-sm Design And Realization

With the increasing development of three networks convergence in our country, the multimedia service like IPTV has been getting greatly improved. Multimedia service has some particular characteristics like high bandwidth consumption which stimulates the development and popularity of IP multicast. The crucial technology of IP multicast is multicast routing which has varieties of multicast routing protocals. Among those protocals, PIM-SM has become most popular due to its advantages such as user taking initiative to join, pan flood control and multicast not limited to a domain.Based on the study of PIM-SM, this paper introduces a distributing implementation scheme of PIM-SM. The idea of the scheme is that the control plane and the data plane of PIM-SM are separately implemented. The protocal control is implemented in the control plane and the data forwarding is implemented in the data plane. The biggest problem is how to assure coherence between control plane and data plane. It introduces a routing synchronization scheme through offsetting algorithm to solve the problem. After a practical testing, the scheme can guarantee the same routing information in control plane and data plane. In short, it is an efficient and feasible routing synchronization scheme. The contents contained are below:(?) Forwarding characteristic and IP multicast architecture are analyzed. The principles and features of PIM-SM are analyzed.(?) Based on the architecture of Comware system and the characteristics of PIM-SM, it introduces a distributing implementation scheme.(?) It analyzes the problem of plane coherence. Based on the implementation structure, it introduces a inner communication mechanics of Comware to solve the problem. It introduces a routing synchronization scheme through offsetting algorithm to solve the problem.(?) Practical testing plan is given. The scheme of PIM-SM proves to be feasible in term of performance. Finally, it analyzes the existing problems and advances the betterment opinion and future work area.