# Joint Deployment Optimization of Parallelized SFCs and BVNFs in Multi-Access Edge Computing
## 2 Recent Works
### Joint Deployment of SFC and BVNFs without Parallelization  
[PERSON] et al. [15] studied a reliability-aware VNF deployment problem by deploying active and backup VNF instances at different cloudlets in the mobile edge network and devised an approximation algorithm. [PERSON] et al. [14] assumed that user satisfaction with a service is heavily impacted by the service's reliability and delay. They formulated a user satisfaction problem aimed at maximizing the accumulative user satisfaction and devising an approximation algorithm for it.  
[PERSON] et al. [16] studied the highly available and cost-effective SFC deployment problem under edge resource limitations and time-varying VNF failures. They proposed a reliability-aware adaptive deployment scheme to deploy SFCs, static backup, and dynamic backup to guarantee reliability. [PERSON] et al. [17] assumed that the reliability of VNF instances is affected by the software implementation, execution duration, workload among edge servers, and so on. They predicted reliability based on digital twin techniques and proposed two optimization problems of reliable service provisioning: the service cost minimization problem and the dynamic service admission maximization problem. [PERSON] et al. [18] proposed an SFC reliability evaluation method and reliability optimization algorithm. They analyzed all of the potential influencing factors for reliability, including resource preemption, common cause failure, fault recovery and redundant backup, and execution time. [PERSON] et al. [19] assumed that the fault probability of each VNF is dynamic and fluctuates according to time and workload. They proposed a long-term provisioning problem to maximize the throughput of receiving requests while minimizing receiving costs and solved it via an online approximation scheme. [PERSON] et al. [20] studied a novel service reliability augmentation problem for each admitted request and designed a deterministic heuristic for the problem without any resource violation.  
[PERSON] et al. [21] focused on a dynamic network environment where a user request arrived randomly and formulated the maximization problem of the number of accepted user requests. [PERSON] et al. [22] formulated dynamic reliability-aware service placement as an infinite horizon Markov decision process to minimize the placement cost and maximize the number of accepted user requests. They designed an iteration algorithm to find the optimal policy. Unlike [PERSON] et al. [22], [PERSON] et al. [23] assumed that requests arrived into the system one by one without the knowledge of future arrivals and proposed a reliable VNF provisioning problem. They developed two efficient online algorithms under two different backup schemes: on-site (local) and off-site (remote) schemes. [PERSON] et al. [24] formulated the problem of SFC scheduling in a dynamic 5G environment aiming to maximize the number of accepted user requests. They first proposed an algorithm to decide the redundancy of VNFs while minimizing delay. Then, they designed a reinforcement learning approach for SFC scheduling to increase the success rate of SFC requests.