# An In-Depth Review on Blockchain Simulators for IoT Environments
## 7 Conclusions  
This paper summarized some of the most popular blockchain simulators and provided a review of the ideal simulator for a specific situation. It also showed that there is an ideal simulator that will fit the requirements for every simulation, but a select few that it is recommended to pick based on the user's needs. When it comes to implementing blockchain in IoT, multiple simulators have been used and tested. Specifically, Hyperledger Fabric, Blocksim, NS3, and Ethereum/Ganache were some of the simulators that stood out in the countless number of simulators discovered. Each of the named simulators have their advantages and limitations and, depending on the simulation, one might be more ideal than the other. As stated, Hyperledger Fabric is a popular platform with a large number of resources. It is an effective simulator to use if only simulating the network layer is desired; however, if other layers are needed, one should look elsewhere. Blocksim can simulate the consensus, and incentive layer in a simple way. In addition, if one desires to easily simulate a large network, Blocksim is a good choice. Despite these capabilities, Blocksim is limited by the number of users who can be part of the network and the amount of data that can be stored. NS3 is a good simulator to use when security and minimal memory waste is crucial to the network. This simulator is capable of running the network and consensus layer. If a user desires to run a different layer, a variant simulator should be picked. NS3 also lacks a GUI which can make it difficult for some users. Although this is true, it still has the benefits previously mentioned. Lastly, Ethereum/Ganache was discussed. Ethereum, in conjunction with Ganache, is a good simulator to choose if one does not want to build a network from scratch, but instead use a prebuilt network. However, transaction times are long, which may not be well suited for most IoT networks. JABS, CBlockSim, and Cardano are just three of the many non-IoT integrated simulators with the potential to work in an IoT environment. These simulators have shown that some of their components can combat the scalability and security issues in IoT devices. A limitation of this paper is that the parameters, such as the block size distribution and geographical node distribution, of the IoT simulators were not discussed in detail. The support of existing or potential consensus algorithms, such as PoW and PoS, were also not a large factor in our study. It should also be mentioned that there are many other simulators that can be discussed, but it is out of the scope of this paper to provide an in-depth review of all of them. This paper aimed to thoroughly provide the advantages and limitations of some of the most promising blockchain simulators for an IoT network, not all of them. One possibility for the future is to direct research to analyze more simulators to find which ones fit the needs of users not mentioned in this paper. Another possibility for future research is to follow the updates and changes made to each prominent blockchain simulator mentioned, to track their improvements and developments. Some key limitations mentioned in this study may no longer exist in the years, or even months to come. By tracking the progress, or lack thereof, users can stay up to date with the simulators and determine which one to use. **Author Contributions:** Conceptualization, Y.W. ; methodology, J.Z., C.D. and Y.W. ; validation, J.Z., S.P., Y.W., W.E. and B.W. ; formal analysis, J.Z., C.D., S.P. and Y.W. ; investigation, J.Z., C.D., S.P. and Y.W. ; resources, Y.W., W.E., G.C.G. and B.W. ; data curation, [PERSON], C.D., S.P., Y.W. and W.E. ; writing--original draft preparation, [PERSON], C.D., S.P. and Y.W. ; writing--review and editing, [PERSON], S.P., Y.W., W.E., G.C.G. and B.W. ; visualization, J.Z., S.P. and Y.W. ; supervision, Y.W., W.E. and G.C.G. ; project administration, Y.W. ; funding acquisition, G.C.G. All authors have read and agreed to the published version of the manuscript.