Web Enabled Devices & home networks

Web Enabled Devices&

home networks

Johan Lukkien

programme leader “home networks”

Eindhoven Embedded Systems Institute

Eindhoven University of Technology

Johan Lukkien 11-4-2001 EESI Embedded Internet Colloquium 2

Overview Evolution of embedded systems and

embedded networking Architecture of Web connected devices Fully networked devices

requirements a few example networks Internet solutions

Conclusion


Embedded Systems evolution

hardware replaces software functionality features

digitisation and manipulation of signals

configuration/programming of systems from outside

completely networked systems

increase in netw

orking


Evolution ofembedded networking

time

standalone fully networked

network aware

network connected

network central


network aware

network connected

network central

Network central: Adapt product design withrespect to the network connection

• Integrate network functions with embedded hardware and software

• Standardisation of connections, protocols

Advantage:• service: access to embedded software:

debugging, replacement, sell features• owner: standardisation, new software

Standalone: embeddedhardware and software:• invisible• are, in fact, an

implementation aspect of the product

Fully networked: the functionality is definedby the network

• Devices controlling each other• Intelligent environments, all equipment in the

background (Philips: “ambient intelligence”)

•

Advantage: http://www.research.philips.com/generalinfo/special/ambintel/index.html

• service: new markets• owner: ease of use, comfort, integration

Network connected: On-line connection withthe system

• Put control hardware/software next to the embedded system

• Interaction!

http://aquarium.eesi.tue.nl

Advantage:• service: diagnostics, leasing of appliances• owner: remote monitor & control, security,

production-control, fleet maintenance

Network aware: Information retrievalfrom the system in a rudimentary fashion

• Status information: errors, wear, use• Using existing connections and resources

already available within the system• Off-line analysis of data• Transport: telephone, Internet

Advantage: • remote diagnosis


time


network aware

network connected

network central


network aware

network connected

network central

The effect of Internet

• Data transport (large distance)

• Standards: ftp, email, ...• Distributed access

Interoperability• Standards for

offering services: Jini, UPnP, OSGi

• Platform for • data exchange• integration

..... + information exchange!!

• Standards for• software architectures• communication: HTTP, Java,

TCP, UDP, ....• visualisation: browsers

• Global addressing


Technical background Moore: number of transistors/mm2 doubles

every 18 months processing power and memory capacity

become abundant Metcalfe: de “value” of a network is

proportional to the square of the number of nodes adding a node benefits existing nodes the larger the network the larger the benefit

Gilder: Internet bandwidth triples every 18 months bandwidth becomes abundant





Conclusion


Architecture

Remote user

Request connection

Program code

HTML browser

AppletES-Server

HTTP server

HTTP

(applet code)

UDP

sensors

actuators


Components HTTP server:

standardized access: URL code download: Java applet

ES server: provide “driver interface” for embedded system

HTTP browser (client): setup contact run machine-independent code “programmable interactive remote control”

Applet: interface to user driver of ES


Trade-offs

ObserverEmbedded

System

Actuators &

Sensors1 2

Connection 1: Internet protocol implicit: within applet protocol explicit:

available to other systems protocol requirements:

access levels of users; security state inspection and modification notification of state changes


Trade-offs

ObserverEmbedded

System

Actuators &

Sensors1 2

Connection 2: proprietary other network, e.g., i/o network, field bus Internet??

bus-like function for Internet aggregation, embedded control

What are the criteria to put intelligence at an actuator/sensor?


Example: ubicom room control

http://www.ubicom.com

Devices not networked individually


Remote user

Request connection

Program code

Example: EESI coffee maker

Switch and heat control not networked individually


Trade-offs

ObserverEmbedded

System

Actuators &

Sensors1 2

Connection 2: proprietary other network, e.g., i/o network, field bus Internet??

bus-like function for Internet aggregation, embedded control

What are the criteria to put intelligence at an actuator/sensor?

Criterion supporting intelligence at A&S• Hardware is locally necessary

• safety, real-time control (don’t distribute safety issues across an unreliable network)

• establishing relationship actuator-sensor• process sensor input

Criteria against intelligence• Single function (ES is already dedicated)• Logical unit controlled from ES• No power available





Conclusion


Fully networked devices Separate user interface and driver functions It must be simple to attach to the network

lightweight easy to handle

Zero configuration connection build a logical network automatically peer to peer in absence of server

Zero configuration interoperable service publication and discovery devices control each other no fixed identification


(Sunbeam) powerline, RF Zero-config for HLT-enabled appliances

identification based on unique device id static definition of devices, services (?)

Proprietary protocol, central control prime target: domotica


Live-in Zanussi (Electrolux, Sweden) Home automation: integrated use of

telephone, powerline and cable auto-config central access point, remote control


Use telephone, powerline Four components: communication-link,

current meter, tele-link, digital adapter Web Ready Appliance Protocol auto-config for WRAP-enabled appliances Console, web connected


Lonworks Echelon, fieldbus technology philosophy: 3 networks (computer, control,

entertainment) use many types of media auto-config,

static typing of

devices deployed in

homes transportation industrial automation


Internet? Concerns the layers above the data-link Until now: mainly supporting computers

not much use of alternatives like powerline (is growing now)

little internet-use within the home Configuration needs

IP address, network mask, router address, domain name, domain name server

TCP/IP stack ... + protocols on top of that


Auto-config issues Level of discovery

physical level (plugging, e.g.“network reset”) network level (broadcasting)

Definition of device static (list of known devices) dynamic

Definition of services static dynamic (publish interface)

Centralized/distributed knowledge Resulting network load


Technologies Connecting:

IP auto configuration: setup a network locally (integral part of IPv6, add-on of IPv4)

choose a link-local address in the absence of a DHCP server

no traffic beyond a router (IPv4, NAT) Apple-talk, Win98

Services: Jini (Sun, Java based) OSGi (Java based) Universal Plug ’n Play (Microsoft)


Jini (Sun) Assuming network connection Centralized information store: lookup

service Upon plugging: discovery & join-in

discover lookup service upload an object implementing the services

(driver) Upon using: obtain driver from the lookup

service; use RMI General classification of services (e.g.,

video source, display, ...)


Universal Plug ’n Play Use IPv4 auto-config or DHCP Simple Service Discovery Protocol

service announcement service request device description: XML document

Service Control Protocol state variables operations

Subscription on state updates Optional user interface URL Fully decentralized solution


Other developments Work of the “zero-configuration

networking” Working Group within IETF Service Location Protocol (supports

queries) Lightweight Directory Service Protocol

to access shared information ....P


Conclusion Growth path for (inter)networking Internet pervasive

but there’s room for a control network connecting control to internet: gateway

Zero-configuration required as devices grow in numbers control each other

IP as platform open standards available software, infrastructure, experience

etc.

Documents

Web Enabled Devices & home networks