Transcript 59-gessler-slides - Security Audit Systems

A Service Platform for
Internet Telephony
Stefan Gessler
Oliver Haase
Andreas Schrader
{Stefan.Gessler|Oliver.Haase|Andreas.Schrader}@ccrle.nec.de
Motivation
PSTN:
Internet:
• network centric
• edge centric
• security,
• flexibility,
• privacy,
• service-orientation
• service quality
• adaptivity
I2N (Intelligent Internet):
• telephony platform combining both approaches
• comprising different component to support various
layers of a telephony system
Motivation (cont’d)
Inter-operability
Telephony
Client
PSTN
Telephony
Client
Gateway
User
Mobility
CORBA
Directory
Server
LDAP
Directory
Server
H.323
LDAP
COUSIN
H.323
COUSIN
Wrapper
Gateway
QoS
Support
AQUARIUS
COUSIN - CORBA Unified Signalling
Active Directories
Usage of LDAP-like CORBA Directories for storage and
retrieval of
• current location of a subscriber (inherent user mobility); the
location is updated automatically whenever a subscriber
registers or unregisters with the system;
• user defined personal information, e.g. postal address, email
address, picture, profession, etc.;
• set of subscribed services (URLs to Java service proxies)
The CORBA Directories provide fully transparent, type
safe access to a globally distributed information base.
Call Setup Signalling
• On
registration of a user, a new signalling state machines (SSM),
running on a distinguished server, is created
• The address of this SSM is stored in user’s personal directory entry
• SSMs are running remotely to put them under network control
• SSM can be envisaged as a signalling proxy of the application
• two peer SSMs communicate via CORBA RMI
• telephony application and its SSM also communicate via CORBA RMI
• the application must provide certain callback methods to its SSM; this
is ensured through a CORBA interface which must be
implemented by each application
Call Setup Signalling (cont’d)
Caller's Home Domain
5
Directory
3
3,5
Internet
Registry
Directory
Directory
Directory
3,5
5
3
1
Directory
Registry
Directory
Callee
5
2
7
4
Caller
Telephony
Application
10
6
SSM
8
Registry
SSM
9
SSM
PeerSSM
Caller's Hosting Domain
Callee's Home/Hosting
Domain
QoS Support
Adaptive Quality of Service
Architecture for Intelligent
Universal Services
• Middleware between Applications and Operating System
• Distributed Collection of QoS Broker, QoS Manager and QoS Control entities
• Real-time Media Capturing, Coding, Streaming, Rendering (JMF and native)
• QoS Scaling, Filtering, Transcoding Mechanisms
• User and Management QoS Policies
• QoS Parameter Interface Provision
• Downloadable Codecs (Software Radio)
• Support of network QoS technologies (DiffServ, IntServ)
• Smoothly integrated in I2N but suitable for any Multimedia Application
Value-Added Services
• services
are split into a movable (service proxy) and a stationary part
• movable part
+ must be implemented in Java
+ can provide a use and a config method
+ communicate with the stationary part over CORBA RMI
+ expose their input and output types through Java reflection
mechanisms; these types can be used to - either statically or
dynamically - combine services to complex services
• stationary part
+ can be implemented in an arbitrary language (due to CORBA)
+ is typically a database, Web server, user directory, ...
Value-Added Services (cont’d)
list of subscribed services
methods for maintainance
of services list
PhoneBook service provides use,
but no config method
frequently used fantastic 4
services, accessible from
main card
Telephony Application
HiTel - Heidelberg Intelligent Telephony
• Prototype Development for demonstrating I2N Concepts
• Java Application (Applet), Swing Graphical Interfaces, JMF Media Panels
• Stateless Collection of Graphical User Interfaces
• User-tailored Service integration by downloading transportable
Service code
• Mechanisms to subscribe, configure, maintain, invoke and withdraw VAS
• ‘Fantastic-4’ Fast Service Invocation Interface
• Concatenation of Services to Chains by Type Filtering Mechanisms
• HTML Browser for Third Party Service Provider Access
• Context-sensitive Help Functionality
Telephony Application (cont’d)
HiTel - Heidelberg Intelligent Telephony
Service
Invocation
Buttons
Main
Menu
Bar
Audio/Video
Control Panel
Multi-Level Gateways
IP Network
SCN
value added/
data services
I²N
I²N
telephony
service
Conclusion
- I2N is an integrated, CORBA-based architecture covering
• basic
call signalling
• mobility support through active directories
• provision
of value added services
• QoS support through AQUARIUS’ adaptive media
transmission
– I2N’s service concept demonstrates the usefulness of Java
technology for downloadable services (proxies)
– Due
to the generic service interface, today’s HiTel telephony
application is able to deal with tomorrow’s (user-tailored)
services
– Even QoS provision can be envisaged as one particular VAS