The Research For A MPLS Based Hierarchical Aggregated Multicast Scheme

The multicast scheme with its 1-to-many property can effectively reduce thenetwork bandwidth requirement of group communications. This multicast method canbe adopted in video conferencing, distance learning, web TV, and duplicated emaildelivery. However, because core routers in multicast systems have to record status ofeach group, the increase of group number causes the increase of core router loading.This result limits multicast's scalability.Though the aggregated tree scheme can reduce the number of status records ofcore routers, meanwhile, it causes extra bandwidth consumption. To solve thisproblem, this proposal develops a hierarchical aggregated tree scheme and appliesMPLS (Multi-Protocol Label Switching) as its switching scheme among aggregatedgroups. It is expected that by reducing the amount of recorded status and bandwidthrequirement, transmission efficiency and multicast application development areenhanced as well.Performance evaluation comparing the hierarchical aggregated multicast schemewith the conventional multicast are conducted using the Network Simulator (ns2).Simulating results demonstrate the superiority of the scheme in reducing the treenumbers, lightening the load of core routers and reducing the unnecessary packets.The paper also analyzed the hierarchy of aggregated multicast and how MPLS isapplied in multicast, which is to be developed in the future.