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Intelligent Environments
Computer Science and Engineering
University of Texas at Arlington
Intelligent Environments
1
Networking for Intelligent
Environments
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Requirements
Technologies
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Networking
Service Discovery
Network Architecture
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Intelligent Environments
Network Requirements
Intelligent Environments
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Sensor 1
Sensor 5
Sensor 2
Sensor 6
Sensor 3
Sensor 7
Sensor 4
Sensor 8
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Network Requirements:
Sensors
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Camera (15) – 320x240, 8-bit color
Motion (15) – distance, direction, velocity
Temperature (12)
Humidity (12)
Light (12) – frequency, intensity
Microphone (12) – 8000 Hz
Gas (4)
Pressure (100)
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Network Requirements:
Sensors
Sensor
Number
Bits/sec (1)
Bits/sec (total)
Camera (320x240)
8-bit color
15
184,320
2,764,800
Motion (dir/dis/vel)
15
48
720
Temperature
12
16
192
Humidity
12
16
192
Light (inten/freq)
12
32
384
Microphone (8KHz)
12
64,000
768,000
Gas
4
16
64
Pressure
100
16
1600
Total
182
248,464
3,535,952
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Other Network Requirements
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Audio
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Phones (16 kHz, 8 bit)
Radios (44 kHz, 16 bit)
TVs (44 kHz, 16 bit)
Media players (44 kHz,
16 bit)
Monitoring (16 kHz, 8
bit)
2.4 Mbits/sec (one
each)
Internet, control, …
Video
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Phones (30fps, 320x240,
8-bit color)
TVs (60 fps, 1024x768,
24-bit color)
Video players (60 fps,
1024x768, 24-bit color)
Monitoring (30 fps,
320x240, 8-bit color)
~6.9 Gbits/sec (one
each)
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Other Network Requirements
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Network Requirements
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Worst-case throughput: 10 Gbits/sec
Maximum throughput: 5 Gbits/sec
Quality of Service (QoS)
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Audio, video
Plug and play (service discovery)
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Intelligent Environments
Network Technologies
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Wired Network Technologies
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Phone line
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Power line
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Home Phoneline Networking Alliance (HomePNA)
X10
Consumer Electronics Bus (CEBus)
HomePlug
LonWorks
New wire
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Ethernet (coax, twisted pair, optical fiber)
Universal Serial Bus (USB)
IEEE 1394 Firewire
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Home Audio Video Interoperability (HAVi)
Specialty: audio, video
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Wireless Network Technologies
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Digital Enhanced Cordless
Telecommunications (DECT)
HomeRF
Bluetooth
IEEE 802.11
HiperLAN2
Infrared
Intelligent Environments
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Phoneline Networking
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Home Phoneline Networking Alliance
(HomePNA)
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IEEE 802.3 (Ethernet)
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www.homepna.org
Carrier Sense Multiple Access with Collision Detect
(CSMA/CD)
10 Mbps (HPNA 2.0)
Length: 500 feet
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HomePNA Packet
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HomePNA Frequencies
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Standard voice (POTS): 20Hz - 3.4kHz
UADSL: 25kHz - 1.1MHz
Home network: 5.5MHz - 9.5MHz
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Phoneline Network Issues
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Random wiring topologies & signal
attenuation
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Home phoneline wiring system is a random “tree”
topology
Simply plugging in the phone or disconnecting the
fax changes the tree
This topology can cause signal attenuation
Signal noise
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Appliances, heaters, air conditioners, consumer
appliances & telephones can introduce signal
noise onto the phone wires
Intelligent Environments
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Powerline Networking
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Ubiquity of power lines
10+ Mbps
Technologies
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X10
Consumer Electronics Bus (CEBus)
HomePlug
LonWorks
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X10
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X10 controllers send signals over
existing AC wiring to receiver modules
X10 technology transmits binary data
using the Amplitude Modulation (AM)
technique
www.x10.com
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X10
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To differentiate the data symbols, the
carrier uses the zero-voltage crossing
point of the 60Hz AC sine wave on the
cycle’s positive or negative transition
Synchronized receivers accept the
carrier at each zero-crossing point
X10 uses two zero crossings to transmit
a binary digit so as to reduce errors
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X10
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Every bit requires a full 60 Hertz cycle and
thus the X10 transmission rate is limited to
only 60 bps
Usually a complete X10 command consists of
two packets with a 3 cycle gap between each
packet
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Each packet contains two identical messages of 11
bits (or 11 cycles) each
A complete X-10 command consumes 47 cycles
that yields a transmission time of about 0.8s
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Consumer Electronics Bus
(CEBus)
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Open standard providing separate physical
layer specification for communication on
power lines and other media
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Electronic Industries Association (EIA-600)
www.cebus.org
Data packets are transmitted by the
transceiver at about 10 Kbps
Carrier Sense Multiple Access/Collision Detect
(CSMA/CD)
Employing spread spectrum technology
(100Hz-400 Hz)
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OSI and CEBus (EIA-600)
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Spread Spectrum Modulation
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Frequency spectrum of a data-signal is
spread using a code uncorrelated with that
signal
Sacrifices bandwidth to gain signal-to-noise
performance
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HomePlug
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HomePlug Powerline Alliance
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www.homeplug.org
Spread-spectrum technology
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HomePlug
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Speed
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Support file transfers at 10BaseT-like rates
Either node-to-node file transfer or scenarios with
multiple nodes performing simultaneous file
transfers
HomePlug 1.0 (14 Mbps)
Voice over IP (VoIP)

Maintain adequate QoS while supporting multiple,
simultaneous VoIP calls while other nodes are
transferring files and during multiple media
streams
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HomePlug
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Interoperability
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Interoperate with other networking technologies
Co-exist with existing powerline networking
technologies such as X-10, CEBus and LonWorks
Security
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Contain strong privacy features
Support multiple logical networks on a single
physical medium
Be applicable to markets in North America, Europe
and Asia
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LonWorks
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Local Operation Networks (LonWorks)
Developed by Echelon Corporation
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www.echelon.com
Provides a peer-to-peer communication
protocol, implementing Carrier Sense Multiple
Access (CSMA) techniques
1.25 Mbps
Works for other wired and wireless media
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LonWorks
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A common message-based
communications protocol
LonTalk protocol implements all seven
layers of the OSI model using a mixture
of hardware and firmware on a silicon
chip
Protocol can be run as fast as 20 MHz
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Powerline Network Issues
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Noise
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Switching power supplies
Wound motors
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Vacuum cleaners, kitchen appliances, drills
Dimmers
Security
Signal attenuation
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New Wire Networking
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Ethernet (coax, twisted pair, optical fiber)
Universal Serial Bus (USB)
IEEE 1394 Firewire
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Home Audio Video Interoperability (HAVi)
Specialty: audio, video
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Ethernet
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IEEE 802.3
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IEEE 802.3ae
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CSMA/CD
Up to 1 Gbps
10GBase-X, 10 Gps
Lengths up to 40 km
www.ethermanage.com/ethernet
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IEEE 802.3
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Universal Serial Bus (USB)
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www.usb.org
480 Mbps
Plug and Play
Hot pluggable
Up to 127 devices simultaneously
Powered bus
5m maximum cable length
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IEEE 1394 Firewire (i.LINK)

Digital interface
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No need to convert digital data into analog
and tolerate a loss of data integrity
Transferring data @ 100, 200, 400 Mbps
Physically small

The thin serial cable can replace larger and
more expensive interfaces
Intelligent Environments
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IEEE 1394 Firewire

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No need for terminators or device IDs
Hot pluggable
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Users can add or remove 1394 devices
with the bus active
Scaleable architecture
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May mix 100, 200, and 400 Mbps devices
on a bus
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IEEE 1394 Firewire
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It can connect up to 63 devices @
transfer rate of 400Mbps
Up to 16 nodes can be daisy- chained
through the connectors
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Standard cables up to 4.5 m in length for a
total standard cable length of 72 m
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IEEE 1394 Firewire
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Flexible topology
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Support of daisy chaining and branching
for true peer-to-peer communication
Non-proprietary
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IEEE 1394b
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1394b is a significant enhancement to the
basic 1394 specification that enables:
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Speed increases to 3.2 Gbps
Distances of 100 meters on UTP-5, plastic optical
fiber and glass optical fiber
Significantly reduces latency times by using
arbitration
Fully backwards compatible with the current
1394 and 1394a specifications
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Home Audio Video
Interoperability (HAVi)

HAVi is a digital Audio Video networking
initiative that provides a home
networking software specification
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Seamless interoperability among home
entertainment products
Designed to meet the particular
demands of digital audio and video
www.havi.org
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HAVi
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Defines operating-system-neutral middleware
that manages:
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Takes advantage of chips built into modern
audio and video appliances
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Multi-directional AV streams
Event schedule
Registries
Provides the management function of a dedicated
audio-video networking system
IEEE 1394 (i. LINK or FireWire) has been
chosen as the interconnection medium
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Specialty Wiring
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Audio
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Video
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Coax
RCA
Speaker wire
Coax
RCA
VGA
~100m maximum cable lengths
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Intelligent Environments
Wireless Networking Technologies
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Wireless Network Technologies
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Digital Enhanced Cordless
Telecommunications (DECT)
HomeRF
Bluetooth
IEEE 802.11
HiperLAN2
Infrared
Intelligent Environments
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General Wireless
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Narrow band
Spread spectrum
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Direct Sequence (DSSS)
Frequency Hopping (FHSS)
Orthogonal Frequency Division
Multiplexing (OFDM)
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DECT
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Digital Enhanced Cordless
Telecommunications (DECT)
www.dectweb.com
Digital radio technology
Dynamic channel selection
Encryption, authentication, identification
500 Kbps – 2 Mbps
Cordless phones
Intelligent Environments
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HomeRF
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www.homerf.org
Shared Wireless Access Protocol
(SWAP)
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IEEE 802.11 for data
DECT for voice
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HomeRF
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Specifications
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2.4 GHz band
FHSS
1.6 Mbps (10 Mbps with SWAP 2.0)
50m range
127 nodes
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Bluetooth
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www.bluetooth.com
Ericsson, the principal inventor,
borrowed the name from Harald
Bluetooth (son of Gorm)
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The King of Denmark circa 900AD
United Denmark and Norway
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Bluetooth
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Specifications
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2.4 GHz
FHSS (79 channels)
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1600 hops per second
Error correction
1 Mbps capacity, 780 Kbps throughput
10m distance
Low power (1 mW)
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Bluetooth
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Personal Area Networks (PANs)
Piconet
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Collection of up to 8 devices using same
hopping sequence
Scatternet
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Collection of piconets, each with different
hopping sequence
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IEEE 802.11
Standard
Frequency PHY Layer
Data Rate
Distance*
802.11a
5 GHz
OFDM
54 Mbps
50m
802.11b
2.4 GHz
DSSS
11 Mbps
100m
802.11e,
MAC layer
Offers QoS and backwards compatibility
(in committee)
802.11g
2.4 GHz
OFDM
54 Mbps
?
* Data rate degrades with distance.
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HiperLAN2
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www.hiperlan2.com
5 GHz
54 Mbps
OFDM
Automatic frequency allocation
TDMA/TDD (Time Division)
QoS support
Intelligent Environments
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Infrared
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www.irda.org
Directed – line of sight
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Diffuse – reflective
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1m range
Limited to room size
Speed
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4 Mbps available
16 Mbps coming
50 Mbps possible
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Wireless Networking
Intelligent Environments
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Wireless Issues
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Distance
2.4 GHz interference
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Microwave ovens
Cordless phones
Security
Not a backbone solution
Intelligent Environments
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Intelligent Environments
Service Discovery
Intelligent Environments
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Service Discovery
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Self-configuring devices
Device becomes aware of network,
network services and other devices
Automatic, as opposed to manual (e.g.,
DHCP, DNS, LDAP)
Several incompatible protocols
Intelligent Environments
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Service Discovery Protocols
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Salutation
Service Location Protocol (SLP)
Jini
Universal Plug and Play
Zero-Configuration Networking
Intelligent Environments
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Salutation
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www.salutation.org
Architecture for looking up, discovering
and accessing services and information
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Salutation
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Abstractions for devices, applications, and
services
Current definitions
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Printers
Fax machines
Document storage devices
Address book
Schedule
Voice message answer, send, storage
More coming (e.g., display, OS)
Intelligent Environments
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Salutation
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Capabilities exchange protocol
Service request protocol
“Personalities” (standardized protocols
for common services)
APIs for information access and session
management
Intelligent Environments
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Service Location Protocol (SLP)




Developed by Internet Engineering Task
Force (IETF)
Applies existing Internet standards to
service discovery problem
www.srvloc.org
www.openslp.org
Intelligent Environments
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SLP Agents

User Agent (UA)


Service Agent (SA)


The SLP User Agent is a software entity that is
looking for the location of one or more services.
The SLP Service Agent is a software entity that
provides the location of one or more services.
Directory Agent(DA)

The SLP Directory Agent is a software entity that
acts as a centralized repository for service location
information.
Intelligent Environments
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SLP Messages

Service Request (SrvRqst)


Message sent by UAs to SAs and DAs to
request the location of a service.
Service Reply (SrvRply)

Message sent by SAs and DAs in reply to a
SrvRqst. The SrvRply contains the URL of
the requested service.
Intelligent Environments
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SLP Messages (cont.)

Service Registration (SrvReg)


Service Deregister (SrvDeReg)


Message sent by SAs to DAs containing
information about a service that is available.
Message sent by SAs to inform DAs that a service
is no longer available.
Service Acknowledge (SrvAck)

A generic acknowledgment that is sent by DAs to
SAs as a reply to SrvReg and SrcDeReg messages.
Intelligent Environments
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SLP Messages (cont.)

Attribute Request (AttrRqst)


Message sent by UAs to request the
attributes of a service.
Attribute Reply (AttrRply)

Message sent by SAs and DAs in reply to a
AttrRqst. The AttrRply contains the list of
attributes that were requested.
Intelligent Environments
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SLP Messages (cont.)

Service Type Request (SrvTypeRqst)


Message sent by UAs to SAs and DAs
requesting the types of services that are
available.
Service Type Reply (SrvTypeRply)

Message by SAs and DAs in reply to a
SrvTypeRqst. The SrvTypeRply contains a
list of requested service types.
Intelligent Environments
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SLP Messages (cont.)

DA Advertisement (DAAdvert)


SA Advertisement (SAAdvert)

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Message sent by DAs to let SAs and UAs
know where they are.
Message sent by SAs to let UAs know
where they are.
Unicast or multicast messaging
Intelligent Environments
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SLP Template Example
template-type=Net-Transducer
template-version=0.0
template-description=
This is an abstract service type. The purpose of the NetTransducer service type is to organize into a single category
all network enabled Transducers which have certain properties.
template-url-syntax=
url-path= ; Depends on the concrete service type.
; See these templates.
sample-units= string L
# The units of sample that the Transducer provides, for instance
# C (degrees Celsius), V (Volts), kg (Kilograms), etc.
sample-resolution= string L
# The resolution of the Transducer. For instance, 10^-3 means
# that the Transducer has resolution to 0.001 unit.
sample-rate= integer L
# The speed at which samples are obtained per second. For
# instance 1000 means that one sample is obtained every millisecond.
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SLP Template Example
template-type=service:Net-Transducer:Thermometer
template-version=0.0
template-description=
The Thermometer is a Net-Transducer capable of reading temperature.
The data is read by opening a TCP connection to one of the ports
in the service URL and reading an ASCII string until an NULL
character is encountered. The client may continue reading data at
no faster than the sample-rate, or close the connection.
template-url-syntax=
url-path
= "ports=" ports-list
port-list
= port / port "," ports
port
= 1*DIGIT
; See the Service URL <port> production rule.
; These are the ports connections can be made on.
location-description=string
# The location where the Thermometer is located.
operator=string O
# The operator to contact to have the Thermometer serviced.
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Jini


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Service discovery for networks of Javaenabled devices
www.sun.com/jini
www.jini.org
Intelligent Environments
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Jini
Intelligent Environments
72
Jini



Services
Lookup
Communications


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
Java-RMI, CORBA, …
Security
Leasing
Events
Intelligent Environments
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Universal Plug and Play


Microsoft’s service discovery approach
IP-based discovery protocols



XML
www.upnp.org
Examples
Intelligent Environments
74
Universal Plug and Play

Devices

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
Containers for services
XML description
Services

Actions (i.e., methods)




Control server
Event server
State (i.e., variables)
XML description
Intelligent Environments
75
Universal Plug and Play

Control points




Retrieve the device description and get a list of
associated services.
Retrieve service descriptions for interesting
services.
Invoke actions to control the service.
Subscribe to the service’s event source. Anytime
the state of the service changes, the event server
will send an event to the control point.
Intelligent Environments
76
UPnP Enabled Device
Device
Service 1
Service 2
UPnP Enabled Device
Control Point
Device
Control Point
Service
UPnP Enabled Device
Root Device
Embedded Device
Service
Service 1
Service
Control
Server
State
Table
Event
Server
Intelligent Environments
Service 2
77
UPnP Interoperability
Control Point
(Pocket PC)
Control Point
(Remote Control)
IP Network
Native Device
(UPnP VCR)
UPnP Bridge
Native Device
(UPnP Alarm Clock)
Lightweight Device
(LonWorks Thermostat)
Non-IP Bus/Networks
Non-UPnP Device
(X-10 Light)
Intelligent Environments
78
UPnP Protocols

Protocols



UDP, TCP/IP, HTTP, XML
Simple Service Discovery Protocol (SSDP)
Generic Event Notification Architecture
(GENA)


Send/receive event notifications using HTTP
over TCP/IP and multicast UDP
Simple Object Access Protocol (SOAP)

XML and HTTP for remote procedure calls
Intelligent Environments
79
UPnP Protocol Stack
UPnP Vendor Defined
UPnP Forum Working Committee Defined
UPnP Device Architecture Defined
SSDP
HTTPMU GENA
(Discovery)
SSDP
HTTPU
(Discovery)
UDP
SOAP
(Control)
HTTP
GENA
(Events)
HTTP
(Description)
TCP
IP
Intelligent Environments
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Zero-Configuration Networking



Zeroconf (www.zeroconf.org)
IETF standard
Objectives




Allocate addresses without a DHCP server
Translate between names and IP addresses
without a DNS server
Find services, like printers, without a directory
server
Allocate IP Multicast addresses without a MADCAP
server

Multicast Address Dynamic Client Allocation Protocol
Intelligent Environments
81
Zeroconf Protocols

Address autoconfiguration





Configure interfaces with unique addresses
Determine which subnet mask to use
Detect duplicate address assignment
Cope with collisions
Name-to-address translation


Multicast DNS
Decentralized
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82
Zeroconf Protocols

Service discovery


Service Location Protocol (SLP)
DNS Service Resource Record


Use expanded DNS for service requests
Multicast address allocation

Zeroconf Multicast Address Allocation Protocol
(ZMAAP)



Allocate unique addresses and maintain them over time
Prevent reallocation of assigned addresses
Be notified of multicast allocation collision
Intelligent Environments
83
Intelligent Environments
Network Architecture
Intelligent Environments
84
Network Architecture

Networking

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

Service discovery


Phoneline, powerline
New wire
Wireless
SLP, Jini, UPnP, Salutation, zeroconf
Communication

CORBA, Java-RMI, DCOM
Intelligent Environments
85
Network Architecture
Intelligent Environments
86