Research Of Multicast Routing Algorithm In NFV With Constraints

Nowadays,with the increasing network scale and data traffic,the traditional network architecture has been unable to meet the requirement of new technologies in the market,and the concept of Network Function Virtualization(NFV)has been introduced for this purpose.The emergence of NFV has greatly improved the flexibility of network deployment,enabling network functions to be allocated on demand,thereby improving resource utilization.In addition,multicast routing,as an efficient transmission method,has a wide range of applications in real life,such as IPTV,video conferencing,and software updates.With multicast transmission,multiple users can share some resources in the network(especially the bandwidth on the link).Studies have shown that multicast can reduce bandwidth consumption by more than 50% in backbone networks compared to unicast communication.In this paper,we combine NFV with multicast routing to study the multicast routing algorithm in NFV architecture.The routing algorithm in NFV aims to minimize the resource consumption of the network to implement the user's service request.Generally speaking,in an NFV network,the implementation of a service request involves two processes: one is to embed the virtual network function(VNF)in the service function chain on the physical node;the other is to find a suitable routing path to make the source and destination be connected.In this paper,we consider multicast routing in NFV from two aspects of quality of service(QoS)and service reliability,and study the multi-source multicast routing problem with QoS constraints in NFV and the reliable multicast routing problem in NFV.The main results and innovations of this paper are as follows:For the problem of multi-source multicast routing with QoS constraints in NFV,a heuristic algorithm is proposed,named Multi-source Multicast Tree Construction(MMTC),to find an approximate optimal routing scheme.The MMTC algorithm allows each VNF in the service chain to be deployed only once on the physical node,thus minimizing the consumption of node resources.Finally,experiments in real network topology show that,compared with other existing algorithms,the MMTC algorithm can reduce the resource consumption by 10%~20%(related to the size of the network),but its time complexity still needs to be improved.For the reliability-constrained multicast routing problem in NFV,this paperdesigns an approximate optimal solution called Reliable Multicast Tree Construction(RMTC).The RMTC algorithm first finds all the routing trees that meet the constraints,and then selects the one with the least resources consumption as the final routing scheme.Through experiments in the real network topology,it can be seen that compared with other existing algorithms,the RMTC algorithm can reduce the routing cost by about 10% at the expense of a certain time complexity.