Intelligent Environments

Intelligent Environments 1

Intelligent Environments

Computer Science and Engineering

University of Texas at Arlington


Networking for Intelligent Environments Requirements Technologies

Networking Service Discovery

Network Architecture



Network Requirements


Sensor 1

Sensor 2

Sensor 3

Sensor 4

Sensor 5

Sensor 6

Sensor 7

Sensor 8


Network Requirements: Sensors 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)


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 192Humidity 12 16 192Light (inten/freq) 12 32 384Microphone (8KHz)

12 64,000 768,000

Gas 4 16 64Pressure 100 16 1600Total 182 248,464 3,535,952


Other Network Requirements Audio

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 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)


Other Network Requirements


Network Requirements Worst-case throughput: 10

Gbits/sec Maximum throughput: 5 Gbits/sec Quality of Service (QoS)

Audio, video Plug and play (service discovery)



Network Technologies


Wired Network Technologies Phone line

Home Phoneline Networking Alliance (HomePNA) Power line

X10 Consumer Electronics Bus (CEBus) HomePlug LonWorks

New wire Ethernet (coax, twisted pair, optical fiber) Universal Serial Bus (USB) IEEE 1394 Firewire

Home Audio Video Interoperability (HAVi) Specialty: audio, video


Wireless Network Technologies Digital Enhanced Cordless

Telecommunications (DECT) HomeRF Bluetooth IEEE 802.11 HiperLAN2 Infrared


Phoneline Networking Home Phoneline Networking Alliance

(HomePNA) www.homepna.org

IEEE 802.3 (Ethernet) Carrier Sense Multiple Access with Collision

Detect (CSMA/CD) 10 Mbps (HPNA 2.0) Length: 500 feet

http://www.homepna.org/


HomePNA Packet


HomePNA Frequencies Standard voice (POTS): 20Hz - 3.4kHz UADSL: 25kHz - 1.1MHz Home network: 5.5MHz - 9.5MHz


Phoneline Network Issues Random wiring topologies & signal

attenuation 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 Appliances, heaters, air conditioners,

consumer appliances & telephones can introduce signal noise onto the phone wires


Powerline Networking Ubiquity of power lines 10+ Mbps Technologies

X10 Consumer Electronics Bus (CEBus) HomePlug LonWorks


X10 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

http://www.x10.com/


X10 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


X10 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 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


Consumer Electronics Bus (CEBus) Open standard providing separate physical

layer specification for communication on power lines and other media 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)

http://www.cebus.org/


OSI and CEBus (EIA-600)


Spread Spectrum Modulation Frequency spectrum of a data-signal is

spread using a code uncorrelated with that signal

Sacrifices bandwidth to gain signal-to-noise performance


HomePlug HomePlug Powerline Alliance

www.homeplug.org Spread-spectrum technology

http://www.homeplug.org/


HomePlug Speed

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


HomePlug Interoperability

Interoperate with other networking technologies Co-exist with existing powerline networking

technologies such as X-10, CEBus and LonWorks Security

Contain strong privacy features Support multiple logical networks on a single

physical medium Be applicable to markets in North America,

Europe and Asia


LonWorks Local Operation Networks (LonWorks) Developed by Echelon Corporation

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

http://www.echelon.com/


LonWorks 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


Powerline Network Issues Noise

Switching power supplies Wound motors

Vacuum cleaners, kitchen appliances, drills

Dimmers Security Signal attenuation


New Wire Networking Ethernet (coax, twisted pair, optical

fiber) Universal Serial Bus (USB) IEEE 1394 Firewire

Home Audio Video Interoperability (HAVi) Specialty: audio, video


Ethernet IEEE 802.3

CSMA/CD Up to 1 Gbps

IEEE 802.3ae 10GBase-X, 10 Gps Lengths up to 40 km

www.ethermanage.com/ethernet

http://www.ethermanage.com/ethernet/


IEEE 802.3


Universal Serial Bus (USB) www.usb.org 480 Mbps Plug and Play Hot pluggable Up to 127 devices simultaneously Powered bus 5m maximum cable length

http://www.usb.org/


IEEE 1394 Firewire (i.LINK) Digital interface

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


IEEE 1394 Firewire No need for terminators or device

IDs Hot pluggable

Users can add or remove 1394 devices with the bus active

Scaleable architecture May mix 100, 200, and 400 Mbps

devices on a bus


IEEE 1394 Firewire It can connect up to 63 devices @

transfer rate of 400Mbps Up to 16 nodes can be daisy-

chained through the connectors Standard cables up to 4.5 m in length

for a total standard cable length of 72 m


IEEE 1394 Firewire Flexible topology

Support of daisy chaining and branching for true peer-to-peer communication

Non-proprietary


IEEE 1394b 1394b is a significant enhancement to the

basic 1394 specification that enables: 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


Home Audio Video Interoperability (HAVi) HAVi is a digital Audio Video

networking initiative that provides a home networking software specification Seamless interoperability among home

entertainment products Designed to meet the particular

demands of digital audio and video www.havi.org

http://www.havi.org/


HAVi Defines operating-system-neutral

middleware that manages: Multi-directional AV streams Event schedule Registries

Takes advantage of chips built into modern audio and video appliances Provides the management function of a dedicated

audio-video networking system IEEE 1394 (i. LINK or FireWire) has been

chosen as the interconnection medium


Specialty Wiring Audio

Coax RCA Speaker wire

Video Coax RCA VGA

~100m maximum cable lengths



Wireless Networking Technologies


Wireless Network Technologies Digital Enhanced Cordless

Telecommunications (DECT) HomeRF Bluetooth IEEE 802.11 HiperLAN2 Infrared


General Wireless

Narrow band Spread spectrum

Direct Sequence (DSSS) Frequency Hopping (FHSS)

Orthogonal Frequency Division Multiplexing (OFDM)


DECT Digital Enhanced Cordless

Telecommunications (DECT) www.dectweb.com Digital radio technology Dynamic channel selection Encryption, authentication, identification 500 Kbps – 2 Mbps Cordless phones

http://www.dectweb.com/


HomeRF www.homerf.org Shared Wireless Access Protocol

(SWAP) IEEE 802.11 for data DECT for voice

http://www.homerf.org/


HomeRF Specifications

2.4 GHz band FHSS 1.6 Mbps (10 Mbps with SWAP 2.0) 50m range 127 nodes


Bluetooth www.bluetooth.com Ericsson, the principal inventor,

borrowed the name from Harald Bluetooth (son of Gorm) The King of Denmark circa 900AD United Denmark and Norway

http://www.bluetooth.com/


Bluetooth Specifications

2.4 GHz FHSS (79 channels)

1600 hops per second Error correction

1 Mbps capacity, 780 Kbps throughput 10m distance Low power (1 mW)


Bluetooth Personal Area Networks (PANs) Piconet

Collection of up to 8 devices using same hopping sequence

Scatternet Collection of piconets, each with

different hopping sequence


IEEE 802.11

Standard Frequency

PHY Layer

Data Rate

Distance*

802.11a 5 GHz OFDM 54 Mbps 50m802.11b 2.4 GHz DSSS 11 Mbps 100m802.11e,MAC layer

Offers QoS and backwards compatibility(in committee)

802.11g 2.4 GHz OFDM 54 Mbps ?

* Data rate degrades with distance.


HiperLAN2 www.hiperlan2.com 5 GHz 54 Mbps OFDM Automatic frequency allocation TDMA/TDD (Time Division) QoS support

http://www.hiperlan2.com/


Infrared www.irda.org Directed – line of sight

1m range Diffuse – reflective

Limited to room size Speed

4 Mbps available 16 Mbps coming 50 Mbps possible

http://www.irda.org/


Wireless Networking


Wireless Issues Distance 2.4 GHz interference

Microwave ovens Cordless phones

Security Not a backbone solution



Service Discovery


Service Discovery 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


Service Discovery Protocols Salutation Service Location Protocol (SLP) Jini Universal Plug and Play Zero-Configuration Networking


Salutation www.salutation.org Architecture for looking up,

discovering and accessing services and information

http://www.salutation.org/


Salutation Abstractions for devices, applications,

and services Current definitions

Printers Fax machines Document storage devices Address book Schedule Voice message answer, send, storage More coming (e.g., display, OS)


Salutation Capabilities exchange protocol Service request protocol “Personalities” (standardized

protocols for common services) APIs for information access and

session management


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

http://www.srvloc.org/

http://www.openslp.org/


SLP Agents User Agent (UA)

The SLP User Agent is a software entity that is looking for the location of one or more services.

Service Agent (SA) 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.


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.


SLP Messages (cont.) Service Registration (SrvReg)

Message sent by SAs to DAs containing information about a service that is available.

Service Deregister (SrvDeReg) 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.


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.


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.


SLP Messages (cont.) DA Advertisement (DAAdvert)

Message sent by DAs to let SAs and UAs know where they are.

SA Advertisement (SAAdvert) Message sent by SAs to let UAs know

where they are.

Unicast or multicast messaging


SLP Template Example template-type=Net-Transducer

template-version=0.0

template-description= This is an abstract service type. The purpose of the Net- Transducer 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.


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.


Jini Service discovery for networks of

Java-enabled devices www.sun.com/jini www.jini.org

http://www.sun.com/jini

http://www.jini.org/


Jini


Jini Services Lookup Communications

Java-RMI, CORBA, … Security Leasing Events


Universal Plug and Play Microsoft’s service discovery

approach IP-based discovery protocols

XML www.upnp.org Examples

http://www.upnp.org/

http://www.oasis-open.org/cover/upnp-examples.txt


Universal Plug and Play Devices

Containers for services XML description

Services Actions (i.e., methods)

Control server Event server

State (i.e., variables) XML description


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.


UPnP Enabled Device

UPnP Enabled Device

UPnP Enabled Device

Control Point

Device

Root Device

Embedded Device

Device

Service

Service 2Service 1

Service

Service 2Service 1

Control Point

Service

StateTable

ControlServer

EventServer


UPnP Interoperability

IP Network

Non-IP Bus/Networks

Control Point(Pocket PC)

Lightweight Device(LonWorks Thermostat)

Non-UPnP Device(X-10 Light)

UPnP Bridge

Native Device(UPnP Alarm Clock)

Control Point(Remote Control)

Native Device(UPnP VCR)


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


UPnP Protocol StackUPnP Vendor Defined

UPnP Forum Working Committee Defined

UPnP Device Architecture Defined

HTTPMU(Discovery)

HTTPU(Discovery)

SOAP(Control)

HTTP(Description)

UDP TCP

SSDP GENA SSDP

IP

HTTPGENA

(Events)


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

http://www.zeroconf.org/


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


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





Network Architecture Networking

Phoneline, powerline New wire Wireless

Service discovery SLP, Jini, UPnP, Salutation, zeroconf

Communication CORBA, Java-RMI, DCOM



Documents

Intelligent Environments