## 7 Conclusions and Open Research Issues  
A comprehensive review of the Tactile Internet (TI) is provided in this paper. This research has explored TI design aspects with the proposed application-centric design architecture and applications. In addition, an in-depth discussion of key applications with proposed illustrative diagrams of use cases and current issues and challenges with potential enablers of the TI are provided. Finally, an extensive review of the related articles on enabling technologies such as 5G, SDN, NFV, Cloud/Edge/Fog Computing, Multiple Access, and Network Coding is presented, keeping in mind that the importance of 5G network design, edge/fog computing, 1 ms RTT, compatible tactile gadgets, core software networking and artificial intelligence competencies come at the leading edge of research challenges.  
The various epitomes of the Internet will be predominated by the rise of the TI that will probably bring real-time control and tactile experiences operating from a remote distance. TI facilitates a new transformation and development in wireless communication for real-time and virtual applications. It will transform pretty much every portion of the general population such that they become familiar with TI services. It is forecasted that cutting-edge 5G network frameworks will support the TI at the wireless edge.  
Three possible future research directions and open issues regarding TI are outlined below: (i) traditional cloud-based computational techniques are adding up to the communication delay in wireless links due to the non-presence of cloud infrastructure near the end user. Therefore, the concept of Edge/Fog computing could be used to bring computational capabilities nearer the end user, and thus would be proved as a promising technology to reduce the RTT compared to the traditional cloud-based infrastructure; (ii) Due to requirements of high data rates and dynamic orchestration of resources in the core network and radio access network (RAN), the concept of network softwarisation in 5G networks would be the potential technology to guarantee end-to-end reliability and meet the less than 1 ms RTT requirement. Thus, to further improve RTT, emerging latency minimisation techniques such as SDN-based and NFV-based design could be the enabling technologies for the core architecture of RAN; and (iii) In a wireless system, various protocol layers take part in the overall RTT. Some fundamental delay components such as transmission delay and queuing delay should be considered in TI implementation. Therefore, effective physical and MAC-layer techniques are needed to improve RTT in the wireless transmission system.  
We are writing to confirm with you that the work presented in this paper is an original contribution. Conceptualisation, V.F.; Methodology, V.F. and N.I.S.; Discussion, V.F., N.I.S. and A.A.-A.; Implementation, V.F.; Validation, V.F. and N.I.S.; Empirical evaluation, V.F. and N.I.S.; Writing--original draft preparation, V.F.; Writing--review and editing, V.F., N.I.S. and A.A.-A.; Project supervision, N.I.S. and A.A.-A.; Correspondence author, N.I.S.; Responded to reviews, V.F. and N.I.S. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors declare no conflict of interest. We also confirm that our survey paper has not been previously published and is not currently under consideration by any other journals. All authors involved have approved the contents of this paper and have agreed to the Journal of MDPI Electronics submission policies.