Towards Deterministic Fault-Tolerant Service Function Slicing in Edge Networks

The ultra-reliable and low latency communication (URLLC) service in 5G/6G will be delivered through a sequence of software-based network functions, also known as a service function chain (SFC). To satisfy the ultra-reliable requirement of the URLLC service, fault-tolerance in URLLC SFC processes is required. However, achieving deterministic fault-tolerance in URLLC SFC delivery is challenging as physical/virtual network failures and hardware/software failures have to be jointly consid-ered. In this work, we first introduce an augmented SF protection graph, called k-connected service function slicing (KC-SFS), which can facilitate the SF protection against multiple concurrent physical/virtual node and physical link failures. Based on the KC-SFS, we define a new problem called deterministic fault-tolerant service function slicing (DFT-SFC) and formulate it with a mathematical model. To solve DFT-SFC, we propose an efficient heuristic algorithm, called service function slice embedding (SFSE), which employs the k-connected network slicing technique (k-NST). Via thorough mathematical analysis, we prove that k-NST achieves 2-approximation. Meanwhile, our extensive experimental results show that the proposed SFSE guarantees deterministic fault-tolerance and outperforms the schemes directly extended from the stste -of - the art.