DistB-Condo: Distributed Blockchain-Based IoT-SDN Model for Smart Condominium
Open accessAbstract
Condominium network refers to intra-organization networks, where smart buildings or apartments are connected and share resources over the network. Secured communication platform or channel has been highlighted as a key requirement for a reliable condominium which can be ensured by the utilization of the advanced techniques and platforms like Software-Defined Network (SDN), Network Function Virtualization (NFV) and Blockchain (BC). These technologies provide a robust, and secured platform to meet all kinds of challenges, such as safety, confidentiality, flexibility, efficiency, and availability. This work suggests a distributed, scalable IoT-SDN with Blockchain-based NFV framework for a smart condominium (DistB-Condo) that can act as an efficient secured platform for a small community. Moreover, the Blockchain-based IoT-SDN with NFV framework provides the combined benefits of leading technologies. It also presents an optimized Cluster Head Selection (CHS) algorithm for selecting a Cluster Head (CH) among the clusters that efficiently saves energy. Besides, a decentralized and secured Blockchain approach has been introduced that allows more prominent security and privacy to the desired condominium network. Our proposed approach has also the ability to detect attacks in an IoT environment. Eventually, this article evaluates the performance of the proposed architecture using different parameters (e.g., throughput, packet arrival rate, and response time). The proposed approach outperforms the existing OF-Based SDN. DistB-Condo has better throughput on average, and the bandwidth (Mbps) much higher than the OF-Based SDN approach in the presence of attacks. Also, the proposed model has an average response time of 5% less than the core model.
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The ever growing number of IoT resources together with relevant applications means the requirement of processing large amount of data.
“The ever growing number of IoT resources together with relevant applications means the requirement of processing large amount of data [98, 99].”
From Federated learning-based AI approaches in smart healthcare: Concepts, taxonomies, challenges and open issues (2023) · cites this paper as [99]
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Software-Defined Networking: A Comprehensive Survey
Kreutz, D., Ramos, F. M. V., Esteves Verissimo, P., Esteve Rothenberg, C., Azodolmolky, S., & Uhlig, S. (2015) · Proceedings of the IEEE · doi:10.1109/jproc.2014.2371999 · Cited by 5,050 · see citing works
5G network slicing using SDN and NFV: A survey of taxonomy, architectures and future challenges
Barakabitze, A. A., Ahmad, A., Mijumbi, R., & Hines, A. (2019) · Computer Networks · doi:10.1016/j.comnet.2019.106984 · Cited by 842 · see citing works
Xie, J., Yu, F. R., Huang, T., Xie, R., Liu, J., Wang, C., & Liu, Y. (2019) · IEEE Communications Surveys & Tutorials · doi:10.1109/comst.2018.2866942 · Cited by 700 · see citing works
Efficient IoT-based sensor BIG Data collection–processing and analysis in smart buildings
Plageras, A. P., Psannis, K. E., Stergiou, C. L., Wang, H., & Gupta, B. B. (2017) · Future Generation Computer Systems · doi:10.1016/j.future.2017.09.082 · Cited by 596 · see citing works
Smart community: an internet of things application
Li, X., Lu, R., Liang, X., Shen, X., Chen, J., & Lin, X. (2011) · IEEE Communications Magazine · doi:10.1109/mcom.2011.6069711 · Cited by 586 · see citing works
OpenDaylight: Towards a Model-Driven SDN Controller architecture
Medved, J., Varga, R., Tkacik, A., & Gray, K. (2014) · IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM) · doi:10.1109/wowmom.2014.6918985 · Cited by 577 · see citing works
Residual Energy-Based Cluster-Head Selection in WSNs for IoT Application
Behera, T. M., Mohapatra, S. K., Samal, U. C., Khan, M. S., Daneshmand, M., & Gandomi, A. H. (2019) · IEEE Internet of Things Journal · doi:10.1109/jiot.2019.2897119 · Cited by 495 · see citing works
NFV: state of the art, challenges, and implementation in next generation mobile networks (vEPC)
Hawilo, H., Shami, A. A., Mirahmadi, M., & Asal, R. (2014) · IEEE Network · doi:10.1109/mnet.2014.6963800 · Cited by 456 · see citing works
Benevolo, C., Dameri, R. P., & D’Auria, B. (2015) · Lecture notes in information systems and organisation · doi:10.1007/978-3-319-23784-8_2 · Cited by 448 · see citing works
Distblocknet: a distributed blockchains-based secure SDN architecture for IoT networks
Sharma, P. K., Singh, S., Jeong, Y.-S., & Park, J. H. (2017) · IEEE Communications Magazine · doi:10.1109/mcom.2017.1700041 · Cited by 428 · see citing works
A Software Defined Networking architecture for the Internet-of-Things
Qin, Z., Denker, G., Giannelli, C., Bellavista, P., & Venkatasubramanian, N. (2014) · IEEE/IFIP Network Operations and Management Symposium (NOMS) · doi:10.1109/noms.2014.6838365 · Cited by 386 · see citing works
A survey: Control plane scalability issues and approaches in Software-Defined Networking (SDN)
Karakuş, M., & Arjan Durresi, A. (2016) · Computer Networks · doi:10.1016/j.comnet.2016.11.017 · Cited by 375 · see citing works
Blockchain based hybrid network architecture for the smart city
Sharma, P. K., & Park, J. H. (2018) · Future Generation Computer Systems · doi:10.1016/j.future.2018.04.060 · Cited by 371 · see citing works
Software Defined Optical Networks (SDONs): A Comprehensive Survey
Thyagaturu, A. S., Mercian, A., McGarry, M. P., Martin Reisslein, B., & Kellerer, W. (2016) · IEEE Communications Surveys & Tutorials · doi:10.1109/comst.2016.2586999 · Cited by 366 · see citing works
An Energy-Efficient SDN Controller Architecture for IoT Networks With Blockchain-Based Security
Yazdinejad, A., Parizi, R. M., Dehghantanha, A., Zhang, Q., & Choo, K. R. (2020) · IEEE Transactions on Services Computing · doi:10.1109/tsc.2020.2966970 · Cited by 346 · see citing works
Palkar, S., Lan, C., Han, S., et al. (2015) · Symposium on Operating Systems Principles · doi:10.1145/2815400.2815423 · Cited by 325 · see citing works
Best: blockchain-based secure energy trading in SDN enabled intelligent transportation system
Chaudhary, R., Jindal, A., Aujla, G. S., Aggarwal, S., Kumar, N., & Choo, K.-K. R. (2019) · Computers & Security · doi:10.1016/j.cose.2019.05.006 · Cited by 276 · see citing works
A Survey of Blockchain: Techniques, Applications, and Challenges
Gao, W., Hatcher, W. G., & Yu, W. (2018) · International Conference on Computer Communications and Networks (ICCCN) · doi:10.1109/icccn.2018.8487348 · Cited by 225 · see citing works
Blockchain-Based Distributed Framework for Automotive Industry in a Smart City
Sharma, P. K., Kumar, N., & Park, J. H. (2018) · IEEE Transactions on Industrial Informatics · doi:10.1109/tii.2018.2887101 · Cited by 225 · see citing works
Khan, F. A., Asif, M., Ahmad, A., Alharbi, M., & Aljuaid, H. (2020) · Sustainable Cities and Society · doi:10.1016/j.scs.2020.102018 · Cited by 218 · see citing works
Real-time GIS for smart cities
Li, W., Batty, M., & Goodchild, M. F. (2019) · International Journal of Geographical Information Systems · doi:10.1080/13658816.2019.1673397 · Cited by 207 · see citing works
Blockchain and fog based architecture for internet of everything in smart cities
Singh, P., Nayyar, A., Kaur, A., & Ghosh, U. (2020) · Future Internet · doi:10.3390/fi12040061 · Cited by 190 · see citing works
A SDN-IoT Architecture with NFV Implementation
Ojo, M. O., Adami, D., & Giordano, S. (2016) · IEEE Globecom Workshops (GC Wkshps) · doi:10.1109/glocomw.2016.7848825 · Cited by 146 · see citing works
A secure IoT architecture for Smart Cities
Chakrabarty, S., & Engels, D. W. (2016) · IEEE Consumer Communications & Networking Conference (CCNC) · doi:10.1109/ccnc.2016.7444889 · Cited by 139 · see citing works
Securing Internet of Things with Software Defined Networking
Kalkan, K., & Zeadally, S. (2017) · IEEE Communications Magazine · doi:10.1109/mcom.2017.1700714 · Cited by 136 · see citing works
Flow Based Security for IoT Devices Using an SDN Gateway
Bull, P., Austin, R., Popov, E., Sharma, M., & Watson, R. (2016) · International Conference on Future Internet of Things and Cloud (FiCloud) · doi:10.1109/ficloud.2016.30 · Cited by 132 · see citing works
DistBlockBuilding: A Distributed Blockchain-Based SDN-IoT Network for Smart Building Management
Rahman, A., Nasir, M. K., Rahman, Z., Mosavi, A., S, S., & Minaei-Bidgoli, B. (2020) · IEEE Access · doi:10.1109/access.2020.3012435 · Cited by 111 · see citing works
Self-citationReurbanization in Toronto: Condominium boom and social housing revitalization
Lehrer, U. A., Keil, R., & Kipfer, S. A. (2010) · disP - The Planning Review · doi:10.1080/02513625.2010.10557065 · Cited by 85 · see citing works
Alcarria, R., Bordel, B., Robles, T., Martín, D., & Manso-Callejo, M.-Á. (2018) · Sensors · doi:10.3390/s18103561 · Cited by 81 · see citing works
Multi-criteria based zone head selection in Internet of Things based wireless sensor networks
Farman, H., Jan, B., Javed, H., Ahmad, N., Iqbal, J., Muhammad, A., & Ali, S. (2018) · Future Generation Computer Systems · doi:10.1016/j.future.2018.04.091 · Cited by 75 · see citing works
BlockChain for IoT Security and Management: Current Prospects, Challenges and Future Directions
Roy, S., Ashaduzzaman, M., Hassan, M., & Chowdhury, A. R. (2018) · International Conference on Networking, Systems and Security (NSysS) · doi:10.1109/nsyss.2018.8631365 · Cited by 63 · see citing works
Blockchain and Artificial Intelligence
Marwala, T., & Xing, B. (2018) · arXiv · doi:10.48550/arxiv.1802.04451 · Cited by 62 · see citing works
Younus, M. U., Islam, S. U., Ali, I., Khan, S., & Khan, M. K. (2019) · Journal of Network and Computer Applications · doi:10.1016/j.jnca.2019.04.002 · Cited by 60 · see citing works
Cloud based management and control system for smart communities: A practical case study
Mital, M., Pani, A. K., Damodaran, S., & Ramesh, R. (2015) · Computers in Industry · doi:10.1016/j.compind.2015.06.009 · Cited by 58 · see citing works
Security in software-defined wireless sensor networks: Threats, challenges and potential solutions
Pritchard, S. W., Hancke, G. P., & Abu-Mahfouz, A. M. I. (2017) · 2022 IEEE 20th International Conference on Industrial Informatics (INDIN) · doi:10.1109/indin.2017.8104765 · Cited by 58 · see citing works
Collaborative housing and blockchain
Aznar, S. N. (2018) · Administration · doi:10.2478/admin-2018-0018 · Cited by 52 · see citing works
Deployment of Robust Security Scheme in SDN Based 5G Network over NFV Enabled Cloud Environment
Abdulqadder, I. H., Zou, D., Aziz, I. T., Yuan, B., & Dai, W. (2018) · IEEE Transactions on Emerging Topics in Computing · doi:10.1109/tetc.2018.2879714 · Cited by 50 · see citing works
Kaur, A., Nayyar, A., & Singh, P. (2020) · doi:10.1002/9781119621201.ch2 · Cited by 50 · see citing works
Amandeep, Bhattacharjee, A., Das, P., et al. (2017) · IEEE Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON) · doi:10.1109/iemcon.2017.8117219 · Cited by 49 · see citing works
Islam, M. J., Mahin, M. S. R., Roy, S., Debnath, B. C., & Khatun, A. (2019) · International Conference on Electrical, Computer and Communication Engineering · doi:10.1109/ecace.2019.8679167 · Cited by 43 · see citing works
Self-citationBurkhardt, D., Werling, M., & Lasi, H. (2018) · IEEE International Conference on Engineering, Technology and Innovation (ICE/ITMC) · doi:10.1109/ice.2018.8436299 · Cited by 41 · see citing works
Rahman, A., Sara, U., Kundu, D., Islam, S., Jahidul, M., Hasan, M., Rahman, Z., & Kamal, M. (2020) · International Journal of Advanced Computer Science and Applications · doi:10.14569/ijacsa.2020.0110980 · Cited by 41 · see citing works
Self-citationRahman, A., Islam, M. J., Sunny, F. A., & Nasir, M. K. (2019) · 2019 2nd International Conference on Innovation in Engineering and Technology (ICIET) · doi:10.1109/iciet48527.2019.9290627 · Cited by 40 · cited 1× · see citing works
“the authors were able to save some energy [44], [45].”
BackgroundSelf-citationCENSOR: Cloud‐enabled secure IoT architecture over SDN paradigm
Conti, M., Kaliyar, P., & Lal, C. (2018) · Concurrency and Computation Practice and Experience · doi:10.1002/cpe.4978 · Cited by 37 · see citing works
Innovation and Challenges of Blockchain in Banking: A Scientometric View.
Arjun, R., & Suprabha, K. R. (2020) · International Journal of Interactive Multimedia and Artificial Intelligence · doi:10.9781/ijimai.2020.03.004 · Cited by 37 · see citing works
IoT and Blockchain Paradigms for EV Charging System
Martins, J. P., Ferreira, J. C., Monteiro, V., Afonso, J. A., & Afonso, J. L. (2019) · Energies · doi:10.3390/en12152987 · Cited by 35 · see citing works
SDN/NFV — A new approach of deploying network infrastructure for IoT
Do, S., Le, L.-V., Lin, B. P., et al. (2018) · Wireless and Optical Communication Conference (WOCC) · doi:10.1109/wocc.2018.8372689 · Cited by 34 · see citing works
Security Architecture for Defining and Enforcing Security Profiles in DLT/SDN-Based IoT Systems
Matheu, S. N., Robles-Enciso, A., Zarca, A. M., et al. (2020) · Sensors · doi:10.3390/s20071882 · Cited by 33 · see citing works
An SDN Based Distributed IoT Network with NFV Implementation for Smart Cities
Mukherjee, B. K., Pappu, S. I., Islam, M. J., & Acharjee, U. K. (2020) · Lecture notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering · doi:10.1007/978-3-030-52856-0_43 · Cited by 32 · see citing works
Self-citationThe smart condo: visualizing independent living environments in a virtual world
Boers, N. M., Chodos, D., Jianzhao, H., et al. (2009) · doi:10.4108/icst.pervasivehealth2009.6020 · Cited by 28 · see citing works
Decentralized Transaction Mechanism Based on Smart Contract in Distributed Data Storage
Gu, Y., Hou, D., Wu, X., Tao, J., & Zhang, Y. (2018) · Information · doi:10.3390/info9110286 · Cited by 25 · see citing works
Optimized Energy Harvesting, Cluster-Head Selection and Channel Allocation for IoTs in Smart Cities
Aslam, S., Hasan, N. U., Jang, J. W., et al. (2016) · Sensors · doi:10.3390/s16122046 · Cited by 24 · see citing works
Blockchains for Smart Cities: A Survey
Ghandour, A. G., Elhoseny, M., & Hassanien, A. E. (2018) · Lecture notes in intelligent transportation and infrastructure · doi:10.1007/978-3-030-01560-2_9 · Cited by 21 · see citing works
Permissioned Blockchain-Based Distributed Software-Defined Industrial Internet of Things
Qiu, C., Yu, F. R., Xu, F., Yao, H., & Zhao, C. (2018) · IEEE Globecom Workshops (GC Wkshps) · doi:10.1109/glocomw.2018.8644520 · Cited by 21 · see citing works
SDN and NFV as Enabler for the Distributed Network Cloud
Hoffmann, M., Jarschel, M., Pries, R., et al. (2017) · Mobile Networks and Applications · doi:10.1007/s11036-017-0905-y · Cited by 20 · see citing works
Blockchain-Based SDN Security Guaranteeing Algorithm and Analysis Model
Shao, Z., Zhu, X., Chikuvanyanga, A. M. M., & Zhu, H. (2019) · Lecture notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering · doi:10.1007/978-3-030-19156-6_32 · Cited by 19 · see citing works
Towards Understanding Internet of Things Security and its Empirical Vulnerabilities: A Survey
Bouanani, S. E., Achbarou, O., Ahmed, M., et al. (2019) · International Journal of Advanced Computer Science and Applications · doi:10.14569/ijacsa.2019.0101048 · Cited by 16 · see citing works
Cost Analysis of SDN/NFV Architecture over 4G Infrastructure
Almustafa, K. M., & Alenezi, M. (2017) · Procedia Computer Science · doi:10.1016/j.procs.2017.08.328 · Cited by 10 · see citing works
Vural, S., Minerva, R., Carella, G., et al. (2018) · IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN) · doi:10.1109/nfv-sdn.2018.8725755 · Cited by 4 · see citing works
Flagged first, then by citations
Research works printed but not linked: 4
- [13][13] A. Kaur, A. Nayyar, and P. Singh, 'Blockchain: A path to the future,' Cryptocurrencies and Blockchain Technology Applications, pp. 25-42, 2020. -
- [25][25] C. Qiu, F. R. Yu, F. Xu, H. Yao, and C. Zhao, 'Permissioned Blockchainbased Bistributed Software-Defined Industrial Internet of Things,' in 2018 IEEE Globecom Workshops (GC Wkshps). IEEE, 2018, pp. 1-7. -
- [36][36] J. Medved, R. Varga, A. Tkacik, and K. Gray, 'Opendaylight: Towards a Modeldriven SDN Controller Architecture,' in Proceeding of IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks 2014. IEEE, 2014, pp. 1-6. -
- [38][38] S. Palkar, C. Lan, S. Han, K. Jang, A. Panda, S. Ratnasamy, L. Rizzo, and S. Shenker, 'E2: A Framework for NFV Applications,' in Proceedings of the 25th Symposium on Operating Systems Principles, 2015, pp. 121-136. -
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Self-citation
- Authors
- Rahman, A., Islam, M. J., Rahman, Z., Reza, M. M., Anwar, A., Mahmud, M. A. P., Nasir, M. K., & Noor, R. M.
- Affiliations
- Mawlana Bhashani Science and Technology University (BD)
- Green University of Bangladesh (BD)
- Deakin University (AU)
- University of Malaya (MY)
- ORCID
- Venue
- IEEE Access
- Published
- 2020
- Volume
- 8
- Pages
- 209594-209609
- ISSN
- 2169-3536 (ISSN-L)
- OpenAlex
- W3098789502
- Cited by
- 66
- References
- 59
- Citations by year
- 2026: 7 · 2025: 4 · 2024: 9 · 2023: 10 · 2022: 17 · 2021: 17 · 2020: 2
- FWCI
- 10.82
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- IEEE Access (publishedVersion, cc-by)
- arXiv (Cornell University) (submittedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Own your potential (DEAKIN) (submittedVersion)
- Figshare (submittedVersion, cc-by)
- arXiv (Cornell University) (cc-by)
- Topics
- Physical Sciences › Computer Science › Information Systems › Blockchain Technology Applications and Security
- Physical Sciences › Computer Science › Computer Networks and Communications › Software-Defined Networks and 5G
- Physical Sciences › Computer Science › Computer Networks and Communications › IoT and Edge/Fog Computing
- Keywords
- software-defined networking, blockchain, network function virtualization, Internet of Things, cluster head selection, energy efficiency, Internet of Things security, attack detection, decentralized security, smart buildings, throughput, response time
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