BIFT Construction Of SDN Switch In Multicast Based On BIER

Multicast is widely used in IPTV,live webcast and other network services.As the constantly expanding network scale,and the increasing diversity of application services,multicast technology based on traditional network architecture has been unable to meet the needs of network development.The inherent features of Software-defined networking(SDN)such as global perspective and programmable make multicast management more efficient and flexible.Traditional multicast routers must maintain a large amount of multicast state information,which results in some problems,e.g.,such as poor scalability,complex multicast protocols,and long route convergence time.Bit index explicit replication(BIER),as a new multicast technology,carries a binary bit string with destination node information in a multicast message,and only needs to perform logic operations on the bit string during multicast communication.These operations can copy and forward the message with the advantages of statelessness and easy expansion and improve the multicast efficiency.In BIER-based multicast,the switch needs to be equipped with a bit index forwarding table(BIFT)to copy and forward multicast packets.The inefficient of BIFT reconstruction will directly affect the transmission performance of the multicast packets,and even cause the interruption of network transmission.This thesis studies a method to quickly reconstruct BIFT for the entire network with SDN switches,to adapt to the constantly changing multicast scale.First,This thesis introduces the current status of traditional multicast and SDN multicast research,and discusses the limitations of current multicast communication technologies.By analyzing the characteristics of BIER's statelessness,high scalability,and rapid convergence,it points out the necessity and key issues of quickly BIFT buiding.Secondly,in view of the efficiency problem of BIFT reconstruction when applying BIER,the multicast routing trees are classified according to the receiver's composition mode,and the BIFT Constructor based on classifying and combining(C3-BIFT)is designed.Multicast subtrees are divided into three types according to the direct successor node set of the root of the tree.Different types of subtrees process the multicast packets in different ways.Starting from the end of the multicast tree,the BIFTs of the root nodes of different subtrees are generated.The subtrees are continuously merged upward,and the BIFT of the root of the merged subtree is continued to be generated until it is the root node of the multicast tree.In C3-BIFT,the BIFTs of all SDN switches are constructed by merging and classifying subtrees in only one multicast routing tree backtracking process.Finally,a BIER-based SDN multicast application is designed and implemented to verify the effectiveness of C3-BIFT.In fixed topology network,based on the different joining methods of multicast members,the joining delay of the host is tested through the multicast application,so as to evaluate the performance of the multicast applying the C3-BIFT algorithm.In randomly generated large-scale network,test the efficiency of C3-BIFT algorithm in building BIFT in large-scale network.The results show that,compared with the conventional multicast network based on the SDN architecture,the delay of the multicast network with the BIER-based multicast receiver is more stable.The C3-BIFT algorithm has little effect on the update time of the flow table and the delay of the multicast join.Further more with the increasing of network scales,BIFT construction time has increased steadily.