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Scalability Evaluation of IoT Cloud Services (L)

Status: Abgeschlossen

Abstract—The Internet of Things is expected to comprise hundreds of billions of devices. This requires high scalability for the cloud services managing and interacting with these devices. With Californium (Cf), we provide a high-performance implementation of the Constrained Application Protocol (CoAP). It outperforms other state-of-the-art CoAP solutions as well as HTTP Web servers. In this work, we want to broaden the evaluation, in particular, by looking at CoAP's push mechanism (Observing Resources). This requires an extension to CoAPBench and conducting several experiments, possibly with a comparison to other protocols such as MQTT.


The Internet of Things (IoT) is the vision of everyday objects that are connected in a ubiquitous network. These objects may be augmented with additional services that make them “smart.” Devices could for instance report their electricity consumption in real-time to match energy demand and supply in the smart grid. Ideally, we interconnect such devices with the largest existing network, the Internet. There, the World Wide Web has evolved to a ubiquitous application layer. Its strengths in interoperability and scalability led to the Web of Things initiative, which adopts approved patterns from the WWW, such as browsing, bookmarking, and the REST architectural style, for machine-to-machine communication. To apply this to resource-constrained devices, the Internet Engineering Task Force (IETF) has standardized the Constrained Application Protocol (CoAP). CoAP shares similarities with HTTP, but also allows for IP multicast, native push notifications, low overhead, and parsing simplicity.

Californium (Cf) is a modular CoAP framework written in Java. It focuses on the service backend for the IoT and provides a high-performance CoAP stack. It also comes with CoAPBench, a benchmarking tool similar to ApacheBench. This tool needs to be extended to benchmark CoAP's observe mechanism. Based on experiments, the observe implementation also might require further optimization. For a master's thesis, the experimental results should be compared to alternative protocols such as MQTT or XMPP.


The student will evaluate and optimize the performance of CoAP Observe in the Californium (Cf) CoAP framework. For that the student shall

  • extend CoAPBench to support benchmarking observe notifications
  • run experiments following scientic standards
  • produce a detailed evaluation of CoAP observe that optionally compares the results to other protocols


  • excellent student who wants to become co-author on a journal paper
  • good knowledge in Java
  • basic knowledge of RESTful Web Services
Student/Bearbeitet von: Marcin Dziezyc, (Matthias Kovatsch)
Contact/Ansprechpartner: Matthias Kovatsch

ETH ZurichDistributed Systems Group
Last updated September 21 2015 12:25:03 PM MET ko