RESIDENTIAL GATEWAY FOR THE INTELLIGENT BUILDING

A design based on integration, service and security perspective

Budi Erixson, Jochen Seitz

Department of Information Technology, Division Communication Networks, Technische Universität Ilmenau, 98693

Ilmenau, Germany

Keywords: Residential gateway, Service gateway, integration

Abstract: In this paper we present the architecture of a residential gateway, which is designed with the OSGi (Open

Service Gateway Initiative) that coordinate with the LDAP (Lightweight Directory Access Protocol) in

order to integrate and connect the various home networks and appliances with the internet securely. The

presented architecture is applied in the intelligent building project, LISTIG (LAN-integrated control system

for intelligent building technique), the cooperation project between Technische Universität Ilmenau,

Desotron (Sömmerda), with the University of Applied Science, Jena and the HFWK (Hörmann Funkwerk

Kolleda GmbH) in Germany. This project is currently still on the progress to achieve the full integration of

the several of home networking technologies, protocols and services.

1 INTRODUCTION

The research and development of intelligent building

applications and home networking technology grow

rapidly, and become an interesting topic for the

industries and science area. On the other side, there

isn’t any intelligent building standardization,

because there are so many perspectives and

approaches to implement it.

The variety of different protocols, home

networking technologies and services are the things,

which cause these different perspectives and

approaches to design and implement the smart

home. The different home network technologies,

which have been developed in order to fulfil the

needs of home networks are IEEE 1394 for

multimedia devices, Ethernet and HPNA for

computing terminals, Bluetooth and WLAN for

mobile devices, Powerline for home appliances.

And there are the mechanisms such as Jini and UPnP

for the device discovery and EHS in order to manage

the integration of new devices into the network.

The natural solution to integrate the diverse and

manifold home networking technologies, protocols

and services is the centred point. And this centre

point is the residential gateway. The implementation

of smart home could be easier when the residential

gateway has the abilities and reliabilities such as:

- can connect the home network with to the

world wide internet

- integrate the various home networking

technologies in house.

- security remote management

- easy to extend and up date the software

In this paper we implement OSGi to design

the residential gateway, because its reliable

characteristics, which are: platform independence,

application independence, multiple service support,

service collaboration support, top level security,

multiple network technology support, and simplicity.

The paper is arranged as follows. Firstly, the

OSGi and its service framework and its service

platform are introduced. Then, the design of the

residential gateway of our project is presented, and

then, the current position with the future work of the

“LISTIG” project is presented. Finally, some

concluding remarks are drawn.

2 OSGI (OPEN SERVICE

GATEWAY INITIATIVE)

OSGi (Open Service Gateway Initiative) was

founded on March 1999 .The Open Service Gateway

Initiative (OSGi) mission is (OSGi, 2003):

- to enable the deployment of services over

wide area networks to local networks and

devices.

Erixson B. and Seitz J. (2005).

RESIDENTIAL GATEWAY FOR THE INTELLIGENT BUILDING - A design based on integration, service and security perspective.

In Proceedings of the First International Conference on Web Information Systems and Technologies, pages 99-103

DOI: 10.5220/0001231500990103

 SciTePress

- to create open specifications for the

network delivery of managed services to

local networks and devices.

2.1 The Framework Specification

The OSGi framework is designed to create

extensible services using the Java programming

language, which provides execution environment for

the needed services. The OSGi framework must

provide a consistent programming model during

application development. The execution

environment extends it with the lifecycle

management, service registry, persistent data storage

and version management.

The OSGi framework provides the lifecycle

management that allows the developers to divide the

applications into self-installable components. These

components are called bundle.

Bundles can be downloaded on demand and

removed when they are no longer needed. When a

bundle is installed and activated in the framework, it

can register any number of services that can be used

by other bundles. This dynamic aspect makes the

software extensible on the device after deployment:

new bundles can be installed for added features or

existing bundles can be updated for bug fixes.

The developers design an application as a set of

bundles that contain services, with each service

implementing a segment of the overall functionality.

The entities in the framework are:

- Services, the Java classes that perform certain

functionality, usually written with interface and its

implementation separated. A service is a self

contained component, accessible via a defined

service interface. In the OSGi model, an application

is built around a set of cooperating services: it can

extend its functionality at runtime by requesting

more services which it requires. The framework

maintains a set of mappings from services to their

implementations and has a simple query mechanism

(LDAP based syntax) that enables an installed

service to request and use the available services. The

Framework manages the dependencies among

services. A developer defines a service as an

interface and provides its implementation. Then she

can register the service with the Framework. When a

service is registered, it can be given a set of

properties (name/value pairs) to enable a

sophisticated retrieval based on LDAP attribute

comparisons.

After a service is published, other services can

use it to accomplish their tasks; they look up the

service from the framework with a search filter, and

will get back the matching service references. The

service reference can then be used to get a Java

object that implements the desired service. The

framework does not actually give out references to

objects implementing a service directly, which

would also instantly create a dynamic dependency

on the bundle providing the service. Instead, it gives

out a ServiceReference object, which can be

stored and passed on to other bundles, without the

implications of dependencies. When the service is

actually to be used by a bundle, a reference to the

implementing object can be obtained from the

current BundleContext, passing it the

ServiceReference.

- Bundles, the functional and deployment unit

for shipping services. A bundle is a JAR (Java

Archive) file that:

- contains the resources to implement zero or

more services.

- contains a manifest file describing the

content of the JAR and providing

information about the bundle.

- states dependencies on other resources,

such as Java packages, that must be

available to the bundle before it can run.

The framework must resolve these

packages prior to starting a bundle.

- designates a special class in the bundle to

act as bundle activator. The framework

must instantiate this class and invokes the

start and stop methods to start or stop the

bundle respectively.

- can contain optional documentation within

the JAR. This can be used to store the

source code of a bundle. Management

systems may remove this information to

save storage spaces.

When a bundle is already started, its

functionality is provided and services are exposed to

other bundles installed in the OSGi environment.

They can then use the framework to access this

functionality. For each bundle installed in the

framework, there is an associated bundle object.

This object is used to manage the namespace of the

bundle's Java classes, by directing the loading and

resolution of those classes. By establishing separate

namespaces for bundles, class-name conflicts among

bundles are avoided.

The framework provides its scoping as an

additional precaution: if two bundles have class

names in common, the fact that those names are

scoped by different bundle namespaces means that

there is no contention. A bundle is used to get

information about the current bundle lifecycle status

and to start, stop and update bundles.

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2.2 The OSGi Service Delivery

The OSGi framework and services exist on the part

of Java environment and the operation system in the

residential gateway. The residential gateway has the

connection with the world wide through the cable

modem or xDSL.

In the home network architecture, the role of the

gateway operator is to control the residential

gateway. The gateway operator uses HTTP for

services and remote management. On the other side,

the appliances in home are connected to each other

through the home networks, which can be accessed

with the service bundles of residential gateway

through the HTTP. And the provider of the OSGi

services is the service provider. The architecture of

the home network architecture, which implements

OSGi residential gateway, is shown in figure 1.

Home network

appliances,

protocols, and

technologies

Internet

(Wide Area Network)

Service

Provider

Gateway

Operator

OSGi Residential Gateway

Client

Figure 1: Service gateway framework

2.3 Lightweight Directory Access

Protocol (LDAP)

Lightweight Directory Access Protocol (LDAP)

provides the protocol to access the directory services

with a unique method to handle a lot of records with

huge volume capacity. LDAP runs over the TCP/IP

or the other connection oriented services. The LDAP

adopts the database and the security model of X.500

protocol and adapts the internet security standard

such as SASL (Simple Authentication and Security

Layer) and SSL/TLS.

In the residential gateway environment, the

LDAP will play not only as a directory service but

as the management engine for the database. The

LDAP is chosen as the directory service, and its

characteristics are:

- Global directory service. LDAP is designed as

the directory service that allows the users to access

the information as the unique identification.

- Open standard and interconnectivity. The

LDAP can be adapted by the vendors or users,

which use the TCP/IP. This makes the connection to

the internet.

- Easy to customize and to extend. It is flexible

to regulate the interface display, and easy to

combine the LDAP with another programs, because

LDAP is an embedded program.

- Security and controlled access protocol. The

authentication process will make the transaction

process more secure.

The LDAP protocol works with client-server

model. The client will send the request or message

to the server, and then the directory server will

answer with its ability in answering the requests at

the same time. The server will read every ID for the

identification. This transaction uses the Basic

Encoding Rules.

There are 9 operations in the LDAP protocol,

which divided into 3 parts. There are:

- Interrogation operation

a. Search (data search operation)

b. Compare (data comparison operation)

- Update operation

a. Add (data addition operation)

b. Delete (data deletion operation)

c. Modify (data modification data operation)

-Authentication and control operation

a. Bind. The processes in this phase are:

- The client makes an authentication to the

directory server.

- The TCP connection, client sends the

distinguished name and authentication mandate.

- The server adjusts the mandate authentication,

and then the answer will be sent to the client.

- If the mandate is rejected, the answer is

anonymous bind

- Authentication process will be finished, when

the connection status is opened, until the client

makes the de-authentication.

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b. Unbind. The interruption connection between

client and server.

c. Abandon. The transaction is cancelled.

3 THE INTELLIGENT BUILDING

DESIGN AND

IMPLEMENTATION

The general and basic architecture of intelligent

building includes these following technology

components:

- Residential gateway

- The home area network

- Broadband access network

- Device access technologies

3.1 Residential Gateway Hardware

Architecture

The basic component, which we use to implement as

the residential gateway is produced by the HFWK

(Hörmann Funkwerk Kolleda GmbH), who

cooperate with the University of Applied Science,

Jena and The Technische Universität Ilmenau, and

Desotron (Sömmerda).

Generally, the fundament of this basic component is

like a normal PC, with the main board, which has

the measurement of 120 x 124 mm, with the

processor, chip graphic, IDE controller, USB

controller, and memory. It has Boot-PROM and 2

PCI sockets.

Below is the technical specification of the hardware

(table 1), which is depicted in figure 2 and it uses

Ethernet (10/100 Mbps) for the broadband access.

Table 1: Hardware technical specification

Main processor

486 Atlas CPU with

math. Coprocessor

Memory 128 MB SDRAM

IDE-Controller 1 channel ATA

Boot-Prom 8 MB Flash RAM

COM-Port 2 x LVTTL

USB-Port 1 x version 1.1

PCI-Bus 2 x standard 32 bit 5V

Keyboard Standard PS/2

Figure 2: Hardware architecture

3.2 Residential Gateway Software

Architecture

The residential gateway software architecture

consists of components or entities. There are:

- The drivers component, that deals with the

various wide area

networks or home area

networks connection of the residential

gateway.

- The operation system and the Java run time

environment

- OSGi framework, that provide an

environment for bundle life cycle and

bundle execution environment

- Bundle services, such as HTTP service,

preferences, log service, device manager,

and administration.

This implementation is the entity of OSGi

service delivery platform, which the software is

embedded in the residential gateway to fulfil the

services and to integrate the various home networks,

appliances, and technologies.

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Figure 3: Software architecture of residential gateway

4 CURRENT STATUS AND

FUTURE WORK

Our system has been written with Java, and we

adopted OSCAR, the free implementation of OSGi

in order to build our OSGi service gateway

specification. This residential gateway is currently

running on the Linux operation system (we use

Blackdown’s java virtual machine). And we are

integrating the LDAP server on our machine in order

to build the OSGi backend system, that enable the

gateway operator to manage the gateway and deliver

the services to the end users, that will give a backup

for the functions like configuration (Upgrade,

update, and search machine) .This system is the

other part to complete the OSGi service delivery

system. Both of the LDAP server and the HTTP

server will be built on the same residential gateway.

There will be then coordination between the LDAP

and OSGi to regulate the residential gateway.

There will be not only the basic services bundles,

but also the LDAP bundle as the bundle service on

the OSGi framework. This bundle will cooperate

with the other bundle services. When the user wants

to search or to operate the services, he has to make

the authentication first. It will increase the security

of the smart home environment.

5 CONCLUSION

In this paper we presented our research progress,

which is the design and implementation residential

gateway for the smart home application, which uses

OSGi. This residential gateway, which integrates the

home networks, appliances, protocols and

technologies, is built with the integration and service

oriented perspective.

The backend OSGi system and the service

gateway platform, which is realized as the

residential gateway software architecture, are the

entities to adopt the OSGi service

delivery system,

which integrates several home networks,

appliances,

protocols and technologies, and to fulfil the needs of

the end users.

The use of LDAP protocol and server, and the

bundle LDAP as one of the services of service

gateway on the residential gateway will give a

positive influence and added value in data base

management and security aspects.

REFERENCES

D.Valtchev and I.Frankov,”Service Gateway Architecture

for a Smart Home”, IEEE Comm. Magazine,

Apr.2002, pp.126-132.

Open service Gateway Initiative Overview, “specification

Overview”,

http://www.osgi.org/resources/doc/spec_overview.pdf

N.Zervos et al, “Hardware Architectures for The Efficient

Implementation of Multi-Service Broadband Access

and Multimedia Home Networks.”

Telecommunication System 23; 34 ,2003, pp.352-367

V.Lawrence,”Digital Gateways for Multimedia Home

Networks”, Telecommunication System, 23:3, 4,

2003, pp.335-349

Markt & Produkt, “Konzepte für die Heimvernetzung” rfe

Sept. 2002, pp.18-20

Funkschau,“Das vernetzte Haus gewinnt Profil“,

Apr.2002, pp.50-52

Markt&Technik,”Gebäudeautomation-rundum sichern”,

Nr.37,Sept.2002, pp.20-22

OSGi Service Platform Release 3, IOS Press, Amsterdam,

March 2003.

K. Hofrichter, “The Residential Gateway as Service

Platform”, IEEE International Conf. On Consumer

electronics, pp. 304-305, USA 2001

Howes, A.Timothy, 1999, “Understanding And Deploying

LDAP Directory Services”, MacMillan Network

Architecture And Development Services, Indianapolis,

USA

Mark Wilcox, 1999, “Implementing LDAP”, Wroxx Press

Ltd, Birmingham, UK

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