Enhanced publish/subscribe in CoAP: Describing advanced subscription mechanisms for the Observe extension

Markel Iglesias-Urkia, Diego Casado-Mansilla, Simon Mayer, Aitor Urbieta

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


In the current Internet of Things (IoT) all sorts of devices and objects with diverse capabilities are being connected to the Internet and the Web. Consequently, new lightweight network protocols are also being developed to connect resource-constrained devices or networks with each other. One of these protocols is the Constrained Application Protocol, which provides a REST architecture to resource and network-constrained devices. Besides the RESTful client-server paradigm, CoAP supports a publish-subscribe model thanks to its Observe extension which mimics some of MQTT's functionalities. However, this extension has some limitations in the subscription mechanism. Hence, this paper proposes several enhancements that define new CoAP options and response codes for such mechanisms. Furthermore, a theoretical comparison of the current CoAP capabilities against the new possibilities is also provided. For that, an specific use case is proposed, and a comparison in terms of the overhead required to exchange payloads and to subscribe to state change notifications on resources.

Original languageEnglish
Title of host publicationProceedings of the 8th International Conference on the Internet of Things, IoT 2018
PublisherAssociation of Computing Machinery
ISBN (Electronic)9781450365642
Publication statusPublished - 15 Oct 2018
Event8th International Conference on the Internet of Things: IoT 2018 - Santa Barbara, United States
Duration: 15 Oct 201818 Oct 2018


Conference8th International Conference on the Internet of Things
Country/TerritoryUnited States
CitySanta Barbara


  • CoAP
  • Constrained Application Protocol
  • Notification
  • Observe
  • Publish/Subscribe
  • Subscription

ASJC Scopus subject areas

  • Human-Computer Interaction
  • Computer Networks and Communications
  • Computer Vision and Pattern Recognition
  • Software


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