Joint Dynamic VNF Placement and Delay and Jitter Aware Multicast Routing in NFV-Enabled SDNs

For reliability, security and scalability, Multicast Request flows (MRs) need to traverse a Service Function Chain (SFC) that consists of series of Virtual Network Functions (VNFs) such as firewalls, encoder-decoder in Network Function Virtualization-enabled Software-Defined Networks (NFV-enabled SDNs). There are typically multiple identical VNF-instances in the network, it brings significant challenges when dynamically choosing or placing the requisite VNF-instances to construct a Service Function Tree (SFT) consisting of SFCs for fulfilling the MRs's routing. This paper investigates the Delay and Jitter Aware Dynamic SFT Embedding and Routing Problem (DJADSERP) considering VNF placement, network resources, delay and jitter constraints as well as network load balance in NFVEnabled SDNs. First, we formulate DJA-DSERP as an integer linear programming model and prove it to be NP-hard. Then, an auxiliary edge-weighted graph and an Optimal Link Selection Function (OLSF) are devised, and SFT Embedding Algorithm (SFT-EA) is proposed to address the problem aiming at minimizing the resource consumption costs while satisfying multiple QoS constraints and network load balance. Furthermore, we theoretically prove the effectiveness of the OLSF and the SFTEA. Simulation results demonstrate that the SFT-EA exhibits superior performance compared to existing algorithms in terms of throughput, traffic acceptance rate, and network load balance.