nhanced CoAP resource discovery - Application layer interfaces and highly targeted query filters

Autor Jawad Ahmad
Date 11. March 2019
Degree Master
Topic Overcoming CoAP's Resource Discovery Limitations
Title Enhanced CoAP resource discovery - Application layer interfaces and highly targeted query filters
Abstract Constrained Application Protocol (CoAP) has the potential to be a key actor in improving
the Internet of Things (IoT) ecosystem. Despite its strengths, CoAP’s standardization is
still under development; thus, CoAP suffers from a lack in maturity in certain regards.
Resource discovery is such an aspect where CoAP’s standard methodology exhibits inad-
equacy. This deficiency is exemplified by a use-case scenario where employing standard
methodology of CoAP’s resource discovery is shown to be inefficient in terms of both time
and space. One of the most significant shortcomings of the standard methodology, in par-
ticular, is its incapability to filter resources based on individual attribute values. This thesis
presents a solution to this limitation by implementing a query processing layer on top of a
standard CoAP server, allowing highly targeted resource filtering. In addition to decreasing
the payload sizes through the use of complex filters, the proposed implementation exercises
the use of Concise Binary Object Representation (CBOR). The performance evaluation has
shown that CBOR reduces payload sizes by as much as 45% when compared to plain-text
encodings such as JavaScript Object Notation (JSON). The performance evaluation also
revealed that for queries that targeted 92% of the total resources, a reduction of up to 54%
response sizes as compared to a standard CoAP server was seen. The proposed implemen-
tation is shown to have successfully filtered resources by attribute values while being time
and space efficient.

Last Modification: 11.02.2020 - Contact Person: M. Sc. Marian Buschsieweke