Resource Discovery in IoT: Current Trends, Gap Analysis and Future Standardization Aspects

Transcription

1 Resource Discovery in IoT: Current Trends, Gap Analysis and Future Standardization Aspects Soumya Kanti Datta Research Engineer, EURECOM TF-DI Coordinator in W3C WoT IG

2 Roadmap Introduction Current Discovery Landscape Gap Analysis from Standards Point-of-View Search Engine Based Resource Discovery Inputs to SDOs Conclusion - p 2

3 Introduction: Discovery Search functionalities provided to Humans Google Yahoo Bing Search Engine for things? Source : - p 3

4 Two Main Aspects to Consider Discovery mechanism is incomplete without retrieving and ranking information. Retrieve Thing description (including properties and capabilities). Thing metadata. Rank Depending on context rank the retrieved information. Discovery for humans Looking for a thing/m2m service providing offline map of Milan. Can be assisted by a search engine. M2M discovery With no human in the loop It is one of the challenges. E.g. - M2M gateway looking for actuators to set a room temperature (smart living service). - p 4

5 Category 1: Search around ME This category of discovery includes technologies that allow to discover things around me (in a spatial sense) NFC UriBeacon (Formerly known as Physical Web from Google) ibeacon (from Apple) Sources p 5

6 Category 2: Search on My Network It covers technologies enabling discovery of things on the network. mdns SSDP - p 6

7 Category 3: Searching in a Directory A central directory is used for discovery of things and resources Discovery requests are sent to the directory. CoRE Resource Directory XMPP IoT Discovery SPARQL Endpoints - p 7

8 Category 4: Search Across Peers In P2P style discovery, the directory is essentially distributed across the peers. Distributed hash tables (DHT) is often used to map the search space into a numeric range and then allocates servers to parts of that range. Observation: the technique works well for scale free networks. - p 8

9 Category 5: Search for Thing Metadata Once a thing" has been discovered with mentioned mechanisms next "resources" (thing metadata) access at thing level needs to be performed Examples CoAP + CoRE Link Format (for thing metadata) Sensor Observation Service (SOS): it is a web service which allows querying sensor metadata. - p 9

10 Category 6: Semantic Based Search Semantic Enhanced Service Proxy Framework for Internet of Things * A semantic based framework using the concept of service advertisement of a smart thing & eases service registration The advertisement contains a service metadata including name, id, endpoint, location and semantic annotation link. An evaluation of semantic service discovery of a U-city middleware ** It proposes a middleware which performs SD using semantic web technologies on the contextual information inferred from sensor data. * ** - p 10

11 Gap Analysis No common catalogue to describe the resources, units and domains. Synonyms are often not recognized. (Rain and Precipitation sensors) Therefore, searching for a resource using a synonym might not discover the resource. No uniform ranking of discovered resources. Secure Discovery: how to integrate security mechanisms and access control functions into a discovery framework. Lack of uniform mechanism for resource discovery. Semantic based discovery is not studied in depth yet. Extract contexts or key words to be used in discovery. How semantics could play a role in maintaining interoperability across IoT platforms. - p 11

12 Search Engine Based Discovery Framework - p 12

13 The Three Layers (1/2) Proxy layer Enable discovery and interaction with smart and legacy things regardless of communication technology and protocols. Discovery layer Configuration registry: manages registration, un-registration of things and provides storage of configurations. Indexing API: registered things are indexed to expedite the search operation. Search engine Receives the discovery request (keywords/parameters) from clients Extracts indices Provides look up facility (discovers the matching things) Ranks the results based on relevance, availability, access control policies. Lifetime: A time period through which resources remain discoverable - p 13

14 The Three Layers (2/2) Service enablement layer Exposes discovery layer functionalities through RESTful web services. Enforces strict access control policies. Provides subscription and notification facilities. Includes semantic components for discovery. Incorporate security mechanisms - p 14

15 Suggestions to SDOs Examine how semantics can solve interoperability issues. Need uniform and technology independent discovery for higher layer applications. Provide guidelines for binding to APIs and protocols for efficient interaction with things. Utilize a uniform catalogue of descriptions (as defined in things description) for discovery of things and their metadata. Provide means of ranking the discovery results When presented to end users or other M2M applications. Integrate strong access control policies and security mechanisms. - p 15

16 Conclusion In a nutshell, Categorization of discovery mechanisms & interaction patterns. Gap analysis from standards perspective A search engine based discovery framework Suggestions to SDOs. A peek into the future works Deploying at a cloud to be used in a smart city framework Deploy in my soon-to-be smart apartment. - p 16

17 Thank you! Telephone: Webpage: - p 17