{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T22:57:29Z","timestamp":1769813849529,"version":"3.49.0"},"reference-count":33,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2016,7,21]],"date-time":"2016-07-21T00:00:00Z","timestamp":1469059200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006338","name":"Vlaamse Interuniversitaire Raad","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100006338","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The Internet of Things (IoT) is expanding rapidly to new domains in which embedded devices play a key role and gradually outnumber traditionally-connected devices. These devices are often constrained in their resources and are thus unable to run standard Internet protocols. The Constrained Application Protocol (CoAP) is a new alternative standard protocol that implements the same principals as the Hypertext Transfer Protocol (HTTP), but is tailored towards constrained devices. In many IoT application domains, devices need to be addressed in groups in addition to being addressable individually. Two main approaches are currently being proposed in the IoT community for CoAP-based group communication. The main difference between the two approaches lies in the underlying communication type: multicast versus unicast. In this article, we experimentally evaluate those two approaches using two wireless sensor testbeds and under different test conditions. We highlight the pros and cons of each of them and propose combining these approaches in a hybrid solution to better suit certain use case requirements. Additionally, we provide a solution for multicast-based group membership management using CoAP.<\/jats:p>","DOI":"10.3390\/s16071137","type":"journal-article","created":{"date-parts":[[2016,7,21]],"date-time":"2016-07-21T09:48:05Z","timestamp":1469094485000},"page":"1137","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":30,"title":["Experimental Evaluation of Unicast and Multicast CoAP Group Communication"],"prefix":"10.3390","volume":"16","author":[{"given":"Isam","family":"Ishaq","sequence":"first","affiliation":[{"name":"Said Khoury IT Center of Excellence (SKITCE), Al-Quds University, Abu Deis, Jerusalem 51000, Palestine"},{"name":"Ghent University\u2014iMinds, Department of Information Technology (INTEC), Technologiepark-Zwijnaarde 15, 9052 Ghent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2039-007X","authenticated-orcid":false,"given":"Jeroen","family":"Hoebeke","sequence":"additional","affiliation":[{"name":"Ghent University\u2014iMinds, Department of Information Technology (INTEC), Technologiepark-Zwijnaarde 15, 9052 Ghent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2377-3674","authenticated-orcid":false,"given":"Ingrid","family":"Moerman","sequence":"additional","affiliation":[{"name":"Ghent University\u2014iMinds, Department of Information Technology (INTEC), Technologiepark-Zwijnaarde 15, 9052 Ghent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Piet","family":"Demeester","sequence":"additional","affiliation":[{"name":"Ghent University\u2014iMinds, Department of Information Technology (INTEC), Technologiepark-Zwijnaarde 15, 9052 Ghent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,7,21]]},"reference":[{"key":"ref_1","unstructured":"Vasseur, J.P., and Dunkels, A. (2010). Interconnecting Smart Objects with IP: The Next Internet, Morgan Kaufmann."},{"key":"ref_2","unstructured":"Dunkels, A., and Yazar, D. (2009, January 4\u20136). Efficient application integration in IP-based sensor networks. Proceedings of the First ACM Workshop on Embedded Sensing Systems for Energy-Efficiency in Buildings, Berkeley, CA, USA."},{"key":"ref_3","unstructured":"Kushalnagar, N., Montenegro, G., and Schumacher, C. IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs): Overview, Assumptions, Problem Statement, and Goals. Available online: https:\/\/tools.ietf.org\/html\/rfc4919."},{"key":"ref_4","unstructured":"Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, J., and Alexander, R. RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks. Available online: https:\/\/tools.ietf.org\/html\/rfc6550."},{"key":"ref_5","unstructured":"Constrained RESTful Environments (core). Available online: http:\/\/datatracker.ietf.org\/wg\/core\/."},{"key":"ref_6","unstructured":"Shelby, Z., Hartke, K., and Bormann, C. RFC 7252-The Constrained Application Protocol (CoAP). Available online: https:\/\/tools.ietf.org\/html\/rfc7252."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"235","DOI":"10.3390\/jsan2020235","article-title":"IETF Standardization in the Field of the Internet of Things (IoT): A Survey","volume":"2","author":"Ishaq","year":"2013","journal-title":"J. Sens. Actuator Netw."},{"key":"ref_8","unstructured":"Rahman, A., and Dijk, E. Group Communication for the Constrained Application Protocol (CoAP). Available online: https:\/\/tools.ietf.org\/html\/rfc7390."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"9833","DOI":"10.3390\/s140609833","article-title":"Flexible Unicast-Based Group Communication for CoAP-Enabled Devices","volume":"14","author":"Ishaq","year":"2014","journal-title":"Sensors"},{"key":"ref_10","unstructured":"Constrained RESTful Environments charter charter-ietf-core-02. Available online: https:\/\/datatracker.ietf.org\/doc\/charter-ietf-core\/."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Reinisch, C., Kastner, W., and Neugschwandtner, G. (2007, January 25\u201328). Multicast communication in wireless home and building automation: ZigBee and DCMP. Proceedings of the 2007 IEEE Conference on Emerging Technologies and Factory Automation, Patras, Greece.","DOI":"10.1109\/EFTA.2007.4416942"},{"key":"ref_12","unstructured":"Colitti, W., Steenhaut, K., and De Caro, N. (2011, January 12\u201314). Integrating wireless sensor networks with the web. Proceedings of the Extending the Internet to Low power and Lossy Networks (IP+ SN 2011), Chicago, IL, USA."},{"key":"ref_13","unstructured":"Hartke, K. Practical Issues with Datagram Transport Layer Security in Constrained Environments. Available online: https:\/\/tools.ietf.org\/html\/draft-hartke-dice-practical-issues-01."},{"key":"ref_14","unstructured":"Hui, J., and Kelsey, R.M. Tulticast Protocol for Low Power and Lossy Networks (MPL). Internet-Draft Draft-Ietf-Roll-Trickle-Mcast-04, IETF. Available online: http:\/\/tools.ietf.org\/html\/draft-ietf-roll -trickle-mcast-04."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1089","DOI":"10.1007\/s11277-013-1250-5","article-title":"Ipv6 multicast forwarding in rpl-based wireless sensor networks","volume":"73","author":"Oikonomou","year":"2013","journal-title":"Wirel. Pers. Commun."},{"key":"ref_16","unstructured":"Greevenbosch, B., Hoebeke, J., Ishaq, I., and den Abeele, F.V. CoAP Profile Description Format. Internet-Draft draft-greevenbosch-profile-description-02, IETF. Available online: https:\/\/tools.ietf.org\/html\/draft-greevenbosch-core-profile-description-02."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Antonini, M., Cirani, S., Ferrari, G., Medagliani, P., Picone, M., and Veltri, L. (2014, January 17\u201319). Lightweight multicast forwarding for service discovery in low-power IoT networks. Proceedings of the 2014 22nd International Conference on Software, Telecommunications and Computer Networks (SoftCOM), Split, Croatia.","DOI":"10.1109\/SOFTCOM.2014.7039103"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Jung, M., and Kastner, W. (2013, January 10\u201313). Efficient group communication based on Web services for reliable control in wireless automation. Proceedings of the 39th Annual Conference of the IEEE Industrial Electronics Society, IECON 2013, Vienna, Austria.","DOI":"10.1109\/IECON.2013.6700071"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1007\/s11390-014-1423-z","article-title":"SeaHttp: A Resource-Oriented Protocol to Extend REST Style for Web of Things","volume":"29","author":"Hou","year":"2014","journal-title":"J. Comput. Sci. Technol."},{"key":"ref_20","unstructured":"MQTT. Available online: http:\/\/mqtt.org\/."},{"key":"ref_21","unstructured":"MQTT-SN. Available online: http:\/\/mqtt.org\/new\/wp-content\/uploads\/2009\/06\/MQTT-SNspecv1.2.pdf."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ishaq, I., Hoebeke, J., Rossey, J., De Poorter, E., Moerman, I., and Demeester, P. (2012, January 4\u20136). Facilitating sensor deployment, discovery and resource access using embedded web services. Proceedings of the 2012 Sixth International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS), Palermo, Italy.","DOI":"10.1109\/IMIS.2012.48"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1145\/354871.354874","article-title":"The Click modular router","volume":"18","author":"Kohler","year":"2000","journal-title":"ACM Trans. Comput. Syst."},{"key":"ref_24","unstructured":"Zolertia Z1. Available online: http:\/\/www.zolertia.com\/ti."},{"key":"ref_25","unstructured":"Rmoni RM090. Available online: http:\/\/www.rmoni.com\/en\/products\/hardware\/rm090."},{"key":"ref_26","unstructured":"Contiki: The Open Source OS for the Internet of Things. Available online: http:\/\/www.contiki-os.org\/."},{"key":"ref_27","unstructured":"Erbium (Er) REST Engine and CoAP Implementation for Contiki. Available online: http:\/\/people.inf.ethz.ch\/mkovatsc\/erbium.php."},{"key":"ref_28","unstructured":"Hinden, R., and Deering, S. IP Version 6 Addressing Architecture. Available online: https:\/\/ tools.ietf.org\/html\/rfc4291."},{"key":"ref_29","unstructured":"Narten, T., Nordmark, E., and Simpson, W. Neighbor Discovery for IP Version 6 (IPv6). Available online: https:\/\/tools.ietf.org\/html\/rfc2461."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Van den Abeele, F., Hoebeke, J., Ishaq, I., Teklemariam, G.K., Rossey, J., Moerman, I., and Demeester, P. (2013, January 11\u201314). Building embedded applications via REST services for the Internet of Things. Proceedings of the 11th ACM Conference on Embedded Networked Sensor Systems, Rome, Italy.","DOI":"10.1145\/2517351.2517426"},{"key":"ref_31","unstructured":"Jennings, C., Shelby, Z., and Arkko, J. Media Types for Sensor Markup Language (SENML). Internet-Draft draft-jennings-core-senml-01, IETF. Available online: https:\/\/tools.ietf.org\/html\/draft-jennings-core-senml-01."},{"key":"ref_32","unstructured":"iMinds iLab.t w-iLab.t. Available online: http:\/\/ilabt.iminds.be\/iminds-wilabt-overview."},{"key":"ref_33","unstructured":"Bouckaert, S., Vandenberghe, W., Jooris, B., Moerman, I., and Demeester, P. (2011). Testbeds and Research Infrastructures. Development of Networks and Communities, Springer."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/7\/1137\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:26:43Z","timestamp":1760210803000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/7\/1137"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,7,21]]},"references-count":33,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2016,7]]}},"alternative-id":["s16071137"],"URL":"https:\/\/doi.org\/10.3390\/s16071137","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,7,21]]}}}