The Key Technology Research Of MPLS Multicast On Broadband Multimedia Trunking Network

Broadband Multi-media Trunking Network should have command, scheduling,broadband multimedia data transmission and other important function. Therefore, toensure the three most important technical indicators in trunking network, like thesetup time of calling, trunking network reliability and security, the paper carried outthe following research works.Broadband multimedia trunking network is a professional mobile systemmeeting command and scheduling for professional application, the most importantfunction is to achieve the ability of rapidily command and scheduling. In the case ofpoint-to-multi-point or multi-point-to-multi-point, trunking network has the highlyquality of group call function, which requires higher quality to design the corenetwork over a public network. Multi-protocol Label Switching(MPLS) is atechnology with switching in the second layer and routing in the third layer, and isbeing a more and more imporant research and applications as a new datatransmission technology. Therefore the combine of MPLS technology and multicasttechnology, it can achieve faster and more accurate data forwarding capability in thecore network, thereby enhancing the fast comand and scheduling functions intrunking network.Since MPLS technology proposed at the beginning, and it did not take themulticast technology into account. Therefore, in the subsequently studies, scholarshave proposed a number of solutions to achieve MPLS multicast. By reading a lot ofliterature, according to the characteristics of broadband multimedia trunkingnetworks, this paper mainly discusses the use of PIM-SM(Protocol IndependentMulticast-Sparse Mode) multicast protocol to support MPLS. On this basis, it madea detailed study for multicast group members to join and prune the MPLS multicastnetwork, and recommends label aggregation to improve the network forwardingspeed, and researches the network survivability mechanism. The main contents ofthis paper are as follows:Research of constructing MPLS multicast tree. To achieve the functions ofMP2MP and P2MP in broadband multimedia trunking network, the paperrespectively researches the shortest path tree and the rendezvous point tree based onPIM-SM protocol to construct the MPLS multicast tree, and simulate the shortestpath in network simulator-2. In the actual network, users can dynamically join andprune the network, so the paper studies the join and prune algorithms andimplemented in NS2.Studies of MPLS multicast label aggregation. Due to the limited number of labels (20bit), if each unicast or multicast task is assigned a label, with theincreasing number of task, on the one hand, the shortage of label number willbecome increasing, on the other hand, it will aggravate the burden of label switchingrouter, resulting in forwarding delays, so the improved mechanism of local labelaggregation mechanism, by finding the maximum same multicast subtree, itimproves the shortage of label and the expansion number of forwarding states.This mechanism proves through mathematical derivation. The nonobjective labelaggregation mechanism is further improving the local label aggregation mechanism,it can further reduce the label switching forwarding states, and to some extent,improve the network flexibility and scalability.Research of MPLS multicast survivability mechanisms. To ensure the securityand reliability requirements in broadband multimedia trunking network, it studiesthe MPLS multicast survivability mechanisms. On the basis of the pinciple ofredundant tree, it is proposed to build the backup RP point to construct the MPLSmulticast tree based on redundancy tree algorithm and the shared trees. Theprinciple is to add two rendezvous points (RP) in the original multicast tree, so thatthe original multicast tree becomes into two level multicast tree. The first level treeis that the source point becomes the new multicast tree’ source point, and constructsthe multicast branching tree based on two RP receiving point, it ensures that thesource node can send multicast packets to the RP; The second level multicast tree isto respectively change two RP into the source point, multicast group members as thereceive multicast tree branching node to construct the MPLS multicast tree,simulated in NS2.