Cost-Effective Reliability-Constrained Multi-Domain Service Function Chain Orchestration: A Metaheuristic Approach

The orchestration of a service function chain (SFC) is responsible for the coordination of multiple virtual network functions (VNFs) in a sequence and the deployment of VNF nodes and links onto physical resources, for the purpose of delivering high-quality network services. This paper studies a multi-domain SFC orchestration problem that aims at minimizing the cost of deploying SFCs across multiple domains while ensuring the overall reliability of SFC requests. We establish a centralized multi-domain framework to formulate the SFC orchestration problem into a combinatorial optimization problem and propose a firefly algorithm (FA)-based metaheuristic approach, named as FA_SFCO, to solve the formulated problem. The proposed FA_SFCO uses a sequence of VNFs in the SFC to represent the orchestration solution, and converts all firefly individuals into valid VNF sequences to facilitate the evolutionary process of FA_SFCO. For each converted VNF sequence, FA_SFCO employs a series of operations, including backup instance allocation, SFC partitioning, and intra-domain mapping, to determine the deployment of all VNFs in the sequence, such that the fitness value of the orchestration in terms of the total deployment cost can be evaluated. Evaluation results on a multi-domain substrate network justify that FA_SFCO outperforms competing algorithms with a significant reduction in deployment cost while meeting the reliability requirement.

I. Introduction

Traditional network services are restricted to proprietary devices, and the implementation of network functions (e.g., deep packet inspection, firewalls, network address translation) relies on dedicated hardware-based middleware [1]. This results in limited flexibility of network services, leading to high costs and operating expenses. Network function virtualization (NFV) [2], which represents a revolutionary paradigm in network architecture, has emerged to solve this problem. NFV aims to decouple traditional network functions from dedicated hardware and migrate them to operate on universal servers, storage, and network devices using software-enabled virtualization technologies. The essential concept of NFV is to implement flexible deployment, rapid configuration, and dynamic scaling of network functions through a software-defined approach, thereby reducing network operating costs, accelerating service delivery, and enhancing network flexibility and scalability. This approach decomposes a network service into a series of virtual network functions (VNFs) [3], which generally follow a specific order. Connecting them strictly in this order forms a service function chain (SFC) [4]. By defining and deploying SFCs, network operators can flexibly configure and manage services in the network and dynamically adjust the processing order and functionalities of network services in an on-demand manner.