IoT Interoperability: A Hub Based Approach

Michael Blackstock, Rodger Lea Human Communication Technologies Lab

Electrical and Computer Engineering Department University of British Columbia

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Motivation• Connection of things to the internet is not enough

• Realize potential of the IoT by providing ability to find, access, manage and (inter)connect things

• Logical next step is to exploit the web - HTTP, JSON, RESTful web services - a “Web of Things”

• MAGIC Broker at IoT 2010; WoTKit at IoT 2012

• Today, large scale hubs store thing data, support search and interaction

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IoT Hubs• General purpose and product-specific

hubs aggregate representation of things and their (meta) data • easier for app developers • can include related data & resources

• Do not (typically) interoperate with each other

• Standardization process necessary to avoid islands of things • Early standardization may stifle

innovation • Need a balanced path toward

Interoperability

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ProfilesHubModel

Path to Hub Interoperability

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IoT Core

Expose things and associated metadata using web protocols.

Minimal interoperability leaving app and tool

developers to do more of the work.

Agreement on approaches and

models e.g. catalogs, things,

groups of things Eases adapter development.

Implementation decisions on resources,

representations, access control and security for hubs.

Direct adapter code reuse is possible.

Ontologies and semantics of things and data. Deeper

integration is possible and little or no

adaptation required.

from experience, refine models, implementation and profiles

IoT Ecosystem Demonstrator

• UK Technology Strategy Board Funded 8 IoT Hubs

• Stimulate development of IoT applications and services

• All 8 in different clusters/domains

• A key goal - interoperability between clusters

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Small IoT Interop

Highways

Airports

Smart Buildings

Transportation

Smart Campus

VehiclesSchools and Education

DISTANCE

IoT-Bay

Approach• Web technologies at the

core, often using existing IoT platforms

• Each consortium implements one or more ‘hubs’

• Hubs communicate with things to expose them to applications

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Things and data

IoT Hub

ApplicationApplicationApplication

Other Hubs

Other Hubs

Other Hubs

TSB Project Interop API• Provide access to “thing” data

and information about what that data represents.

• Focus on interface between applications and hub. Use data from at least one other hub.

• Lightweight, minimal requirements for exchanging catalogs of things - HyperCat

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Things and data

IoT Hub

ApplicationApplicationApplication

Other Hubs

Other Hubs

Other Hubs

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HyperCat• Open catalogue format for

collections of web resources • not just IoT resources • JSON format where ‘things’

identified as resources (URLs)

• RDF-like relationship/value pairs describe what thing resources represent or data associated with things

• defines CRUD operations • basic search, security

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Catalogue Description

Simple Catalogue{ "item-metadata":[ { “rel”:”urn:X-tsbiot:rels:isContentType", "val":"application/vnd.tsbiot.catalogue+json" }, { “rel":"urn:X-tsbiot:rels:hasDescription:en", "val":"Bare catalogue" } ], “items":[ ! { "href":"http://hub.com/resource1", “i-object-metadata”: [ { “rel":"urn:X-tsbiot:rels:hasDescription:en", "val":"The first resource" } ] }, ! { "href":"http://hub.com/resource2", “i-object-metadata”:[ { “rel":"urn:X-tsbiot:rels:hasDescription:en", "val":"The second resource”}] } ] }

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Item Descriptions

Catalogue supports “Simple Search”

Dataset Item URL

HyperCat for open data

Mandatory meta data - description and content type

{ "item-metadata" : [ { "rel" : "urn:X-tsbiot:rels:isContentType",! "val" : "application/vnd.tsbiot.catalogue+json"! },! { "rel" : "urn:X-tsbiot:rels:hasDescription:en",! "val" : "Smart Streets data catalogue that contains static resources."! },! { "rel" : "urn:X-tsbiot:rels:supportsSearch",! "val" : "urn:X-tsbiot:search:simple"! }! ],! "items" : [ !

{ "href" : “/cat/data/average-temperature-and-rainfall-england-and-wales",! "i-object-metadata" : ![ { "rel" : "urn:X-smartstreets:rels:lastUpdate",!

"val" : "2013-06-19T00:00:20.761429"! },! { "rel" : "urn:X-smartstreets:rels:hasId",! "val" : "3f952707-b04e-4a32-a807-a53b6fa0ee58"! },! { "rel" : "urn:X-smartstreets:rels:hasLicense",! "val" : "UK Open Government Licence (OGL)"! },! { "rel" : "urn:X-smartstreets:rels:hasName:en",! "val" : "average-temperature-and-rainfall-england-and-wales"! },! { "rel" : "urn:X-tsbiot:rels:hasDescription:en",! "val" : "Average temperature and total rainfall in England and Wales : 1845 to 2010"! },! { "rel" : "urn:X-smartstreets:rels:tags",! "val" : "average-rainfall,average-temprature,england,new-tag-1,new-tag-2,wales"! },! { "rel" : "urn:X-smartstreets:rels:hasVisibility",! "val" : "public"! },! { "rel" : "urn:X-tsbiot:rels:isContentType",! "val" : "application/vnd.tsbiot.catalogue+json"! },! { "rel" : "urn:X-tsbiot:rels:supportsSearch",! "val" : "urn:X-tsbiot:search:simple"! },! { "rel" : "urn:X-tsbiot:rels:containsContentType",! "val" : "application/vnd.ms-excel"! }! ]! },! { ... additional items ... }! ]!}

exact match on rel or value

• WoTKit IoT Platform at the core

• Static data management: CKAN Open Data Portal

• HyperCat API Proxy

• Landing site and Hub ‘App Store’

Smart Streets Hub

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HyperCat API Proxy

CKAN Open Data Portal

Static Data Files

Landing Site

Apps Apps Apps

WoTKit IoT Platform

Sensor Gateways

Sensor networks and

real time updates

WoTKit• Web-centric IoT Toolkit - IoT 2012 • Thing data manager and

aggregator • 2 way: sense or control • Visualizations • Finding & sharing things • Access control and search by

organizations, groups, tags, meta data

• Real time processing and alerts • Commercialized by Sense

Tecnic Systems

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Architecture• Management and

visualization UI

• Processing engine

• RESTful API

• Shared Thing Data Model

• Time series data store, meta data index for search, message broker for real time data processing

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WoTKit Processor• multi-user real time IoT

data and service mashup tool.

• Visual data flow language for sensors and services.

• See Web of Things Workshop paper for details

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CKAN Data Portal• Driven by need for related

static data storage

• CKAN Open Data portal platform used by many governments

• publishers upload datasets consisting of data resources

• API for search, up/downloading data

• extensible with plugins

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HyperCat API Proxy• Static Implementation - Imports

catalogues from underlying systems to Solr. • Out of date between imports • Security: visibility and access

control logic

• Dynamic Implementation - Get underlying catalogue on request and filter as needed. • Unify access control • Address mismatch between

search semantics • Scale of catalogue - paging

needed

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Smart Streets Experience• In operation for 1 year ~64,000

sensor feeds

• Private and public data about transportation and highways, fixed assets and live sensors.

• Live road traffic, gully levels, air quality, weather, flooding, fixed asset: signs, roads, barriers, parking locations, planned roadworks.

• Sensors upload automatically via APIs. Assets uploaded manually.

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Hub Applications• ‘App store’ on the hub

landing site • Developed by partner

companies and hackathon • Catalog Explorer • Roadworks Mashup • Cycle Spot • Accident reporter • Pothole Prediction • School Run …

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https://smartstreets.sensetecnic.com/app-browse/

Lessons• UK project successful - innovation maintained while achieving a

minimal degree of interoperability

• Too early to standardize everything, need more experience and to establish best practices first

• balance (proprietary) innovation and open standardization

• Cloud-hosted web-based hubs allow abstraction of connectivity details and allowed us to pull together variety of sub-systems and data services.

• Simple catalogue spec made it easier to agree, and provided flexibility on the type and scope of ‘things’ exposed by hubs

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Conclusions• Interoperability is critical to achieving widest variety of

applications and services in the IoT

• A web-centric, hub-based approach is a logical first step toward allowing web developers to access ‘things’ and associated data

• A key challenge is to unify hub catalogues, then thing data. HyperCat is a good first step toward catalogue interoperability

• Tools such as the API Proxy can be used to address catalogue and data interoperability while standards like HyperCat evolve

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More Information• HyperCat:

http://www.hypercat.io/ http://wiki.1248.io/doku.php?id=hypercat!

• Smart Streets: https://smartstreets.sensetecnic.com/

• WoTKit: ! ! http://wotkit.sensetecnic.com/!

• Sense Tecnic Systems: http://sensetecnic.com/ @sensetecnic!

• See demo and paper on distributed data flow at WoT Workshop

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Thanks to Mark Duppenthaler, Daniel Yuen, Smart Streets IoT project Team - In Touch, Lancaster University, Other 8 IoT hub projects - HyperCat specification, UK TSB, Canada NSERC