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Thoughts on how Internet Standards - HTTP, TCP/IP, WiFi, Bonjour - can be used in conjunction with Semantic Web technologies to create the Internet of Things. The emphasis of this document is the home / LAN, hence "The Intranet of Things", but the broad themes are universally applicable. Things that are up in the air are marked in read. Everything IMO. Also see http://iotdb.org - a work in progress.
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Building Blocks of The Internet of Things
@ Home
Wednesday, 17 July, 13
IMO
David Janes@dpjanes
[email protected]://imadeit.davidjanes.com/
July 2013
Wednesday, 17 July, 13
AKA “The Intranet of Things”
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Important!
The Internet of Machinesis just
The Internet with Machines!
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The Building Blocks of the Internet @ Home?• Wi-Fi
• TCP/IP
• URLs / DNS
• HTTP
• HTML / JS / CSS
• JSON / XML
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The same tech enables The Intranet of Things
... more or less ...
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What are the issues?
• Communication
• Discovery
• Control
• Interoperability
• Security
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Communications
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Communications
• How will things talk to things?
• How will we talk to things?
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Protocols
• Wi-Fi
• TCP/IP
• HTTP
• JSON / XML ... for things to things
• HTML ... for us to things
• Bluetooth Low Energy (special case)
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Bluetooth Low Energy
• Ships in all modern iOS devices
• Ships in many new Androids
• 30m range (50m claimed)
• Coin-cell-sized devices
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BLE purpose
• for small sensors and devices
• for personal area networks
• for health stuff ... scales, heart-rate monitors, etc.
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BLE use
• Think of it as “invisible wires”
• Will be controlled...
• directly by mobile devices
• indirectly through hubs
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Discovery
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“Google for my home”
• find what’s available...
• ... and what can I do with it?
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Bonjour
• Lightweight Service Discovery
• Standard needed for specifying how to find IoT services / APIs
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Control
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APIs
• IoT devices are controlled by APIs
• URLs ... from Bonjour Discovery
• HTTP
• JSON
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REST
• URLs describe things ... not actions
• /api/light-2 ✓
• /api/light-2/off ✗
• Stateless
• ... lots of other stuff ...
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HATEOAS
• Always explicitly use URLs ... not numbers or special codes
• “devices” : [ “/api/light-1”, “/api/light-2” ] ✓
• “devices” : [ 1, 2 ] ✗
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JSON
GET /api/devices{ "devices" : [ "/api/light-1", "/api/light-2" ]}
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JSON
GET /api/light-1{ "on" : true, "brightness" : 0.5, "color" : "#FFFFFF"}
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JSON
PUT /api/light-1{ "on" : false}
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Interoperability
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Can...
• devices easily talk to each other?
• devices be controlled from one UI?
• “novel” devices be effortlessly introduced?
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Standards?
• Fine grained / line level ... not on
• Everyone always does their own thing
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But we’re almost there!
• Our standards stack gets us a long way
• i.e. Wi-Fi, HTTP, REST, HATEOAS, JSON
• We just need one last bit of translation
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The Semantic Web
• A kind of wide-open database, use what you need, infinitely extendable
• Everything described by URLs
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schema.org
• Vocabulary for describing things and products (and more)
• e.g. this is a Toshiba 42” Flatscreen TV
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iotdb.org
• A work in progress!
• Vocabulary for describing how to control IoT things
• e.g. this is a light, this can be turned on and off, this has a brightness control, this has a color
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JSON-LD
• Links JSON documents to the Semantic Web
• Too clumsy / difficult for the IoT
• Developers are not likely to adopt ...
• ... but the technique is perfect
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The Rosetta Stone
• Add a single definition term to APIs{
"@iot" : "/definitions/light", "on" : true, "brightness" : 0.5, "color" : "#FFFFFF" }
• Defines every term in the API semantically with well-known definitions
• Another work in progress!
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Security
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We Can’t...
• Hide the devices / APIs
• Make everyone log into every device
• Get this wrong!
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Considerations
• Some attributes can be read by everyone but only set by a few ... e.g. temperature
• Current implementations are bad
• AirPlay: wide open
• UPnP: broken
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Wide open
• Sorry, I’ve got nothing
• This can’t be half-baked
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Device Limitations
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Not that smart
• We need information outside the device
• e.g. Belkin WeMo: I can be on, I can be off
• There’s so much more we need to know!
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What is it really?
• Consider the WeMo
• connected to a table lamp
• connected to a space heater
• It doesn’t know!
• Same interface, effectively / collectively a very different device
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Where is it?
• Is it in the kitchen? in the living room?
• Both? ... e.g. a door open sensor
• Many? ... e.g. a HVAC subsystem
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Wide open
• Assume there’s data that needs to be “outside” the device
• But we don’t want to “go to the Internet” to control our house!
• Open problem
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Get in touch!
David Janes@dpjanes
[email protected]://imadeit.davidjanes.com/
Wednesday, 17 July, 13
