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.
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.
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
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
- 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
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
- 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.
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
protocols, and
(Wide Area Network)
OSGi Residential Gateway
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.
RESIDENTIAL GATEWAY FOR THE INTELLIGENT BUILDING: A design based on integration, service and security
b. Unbind. The interruption connection between
client and server.
c. Abandon. The transaction is cancelled.
The general and basic architecture of intelligent
building includes these following technology
- Residential gateway
- The home area network
- Broadband access network
- Device access technologies
3.1 Residential Gateway Hardware
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
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
- The operation system and the Java run time
- 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.
Figure 3: Software architecture of residential gateway
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.
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,
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.
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RESIDENTIAL GATEWAY FOR THE INTELLIGENT BUILDING: A design based on integration, service and security