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Programmable Architecture for the
Creation and Seamless Control of
Hybrid Services
Constant Gbaguidi
Swiss Federal Institute of Technology (Lausanne)
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Outline
• Problem Statement
– Need for a creation and control architecture, with well-defined service
components
• Our approach
–
–
–
–
Service-centricity, as opposed to network- and end-system-centricity
Programmability: changing the behavior of a system through an API
Smooth migration from existing infrastructures to more “futuristic” ones
Use of tools that can be understood by Telecom as well as Internet people
• Case studies
– Voice-Access-to-Content, Closed User Group (CUG)
• Related Work
• Conclusion
Creation and Control of Hybrid Services
2
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Scope of Hybrid Services
Telecommunication
Hybrid Services
services
Conference
IN VPN
Voice Mail
Call Forwarding
Mobility
Voice Access to
Content
Telecommuting
Teleconference
Integrated VPN
Internet services
Conference
Internet VPN
Email and Voicemail
Chat (IRC)
Content services (Web)
Electronic commerce
•
Hybrid services are not re-implementations of existing services
•
They allow access to services already implemented on either telecommunication or IP networks
•
They allow unique implementation of services, which can still be accessed from any network
•
They pave the road to the provision of future services that do not rest on only one network
Creation and Control of Hybrid Services
3
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Problem Statement
• How to create and control hybrid services?
– Control:
• Provision of a service binding layer that permits passing service control information
across networks (Today we have interoperability at the media transfer and media control
layers)
– Creation:
• Specification of components out of which services can be built (The components must
make sense to both Telecom and Internet communities)
• Mapping of the components onto the service system elements
Freephone
service logic
IP network
Caller
Creation and Control of Hybrid Services
PSTN
H.323 gateway
Callee
4
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
An Overview of Our Solution
Service
Creation
Environment
Java Service Layer
Programmability
API
Cellular
Network
Internet
PSTN
(and N-ISDN)
API: Application Programming Interface
Creation and Control of Hybrid Services
5
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
An Overview of Our Solution (cont’d)
Service
Creation
Environment
Java Service Layer
Programmability
API
Terminal
Workstation
Smart phone
Network Node
Switch
Router
Wireless LAN Node
GSM Base Station
Control Server
IN Service Ctrl Point
H.323 gatekeeper
DHCP server
DNS
Gateway
H.323 gateway
Firewall
API: Application Programming Interface
Creation and Control of Hybrid Services
6
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Architecture of Our Solution
CT/Si: Subsystem on Terminal for Service #i
CN/Si: Subsystem on Network node for Service #i
CC/Si: Subsystem on Control server for Service #I
CG/Si: Subsystem on Gateway for Service #i
SS:
Service Subsystem
Beans Archive
Service
Creation
Environment
Service Factory
1. Identify service
components
Service Instance
SS
SS SS
2. Download the components
Controller
Java
Service
Layer
ST/
S1
Controller
ST/
S2
SN
/S1
Controller
SC/
S1
SC/
S2
Controller
SG
/S1
Service binding
Service binding
Service binding
Service binding
Terminal
Network Node
Control Server
Gateway
Creation and Control of Hybrid Services
3. Build the
binding
layer
7
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
1. Service Modeling: A Way to Identify Components

A Service is composed of features, each of which is associated with an object model.
Classes in the models are the sought components
Key:
Object class
Customer
defines *
Service
Inheritance
Composition
Association class
interacts with
Address
Translation
Security
Creation and Control of Hybrid Services
Charging
Feature
Call control
involves
Connectivity
User Interaction
8
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
1. Example: Address Translation
End-system
•
•
•
•
Key:
End-system is a generic
concept that embraces
terminals, gateways,
information converters,
multipoint control units, etc.
The user makes use of a
device (e.g., a Smart Card)
that has an address
The user may have a higher
level address (e.g., email
address)
The user can bind addresses
with one another
Creation and Control of Hybrid Services
Object class
Device
1
has 1
Inheritance
Composition
Device
Address
Association class
*
uses
1
User
manages
*
Address
Binding
1
Address
1
1
has
*
User Address
Device Address
User Address
9
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Architecture of Our Solution
CT/Si: Subsystem on Terminal for Service #i
CN/Si: Subsystem on Network node for Service #i
CC/Si: Subsystem on Control server for Service #I
CG/Si: Subsystem on Gateway for Service #i
SS:
Service Subsystem
Beans Archive
Service
Creation
Environment
Service Factory
1. Identify service
components
Service Instance
SS
SS SS
2. Download the components
Controller
Java
Service
Layer
ST/
S1
Controller
ST/
S2
SN
/S1
Controller
SC/
S1
SC/
S2
Controller
SG
/S1
Service binding
Service binding
Service binding
Service binding
Terminal
Network Node
Control Server
Gateway
Creation and Control of Hybrid Services
3. Build the
binding
layer
10
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
2. Component Download
0. put persistent
component c: C
on server
Service
instance
Web server
1. execute(C c, URL url)
2. get c
Controller
3. configure
underlying element
Creation and Control of Hybrid Services
11
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Architecture of Our Solution
CT/Si: Subsystem on Terminal for Service #i
CN/Si: Subsystem on Network node for Service #i
CC/Si: Subsystem on Control server for Service #I
CG/Si: Subsystem on Gateway for Service #i
SS:
Service Subsystem
Beans Archive
Service
Creation
Environment
Service Factory
1. Identify service
components
Service Instance
SS
SS SS
2. Download the components
Controller
Java
Service
Layer
ST/
S1
Controller
ST/
S2
SN
/S1
Controller
SC/
S1
SC/
S2
Controller
SG
/S1
Service binding
Service binding
Service binding
Service binding
Terminal
Network Node
Control Server
Gateway
Creation and Control of Hybrid Services
3. Build the
binding
layer
12
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
3. Service Binding Layer
Element {
openConnection,
pauseConnection,
resumeConnection,
releaseConnection,
bindConnections,
transferConnection,
handleEvent
}
e.g., TAPI,
CallPath API, SS7
API, IN API
Creation and Control of Hybrid Services
Binding components
(e.g., security, download)
Java RMI
System element
interface
Enterprise components
(e.g., RMI<->CORBA,
EJB)
Element
13
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
3. A Way to Interface with Elements
Java Service Layer
Interruptions, APIs,
SNMP, H.323, IN
Element
Element
Trigger-Event-Listener
(implements methods to
handle the events caught)
Trigger-Event-Source
Creation and Control of Hybrid Services
Network Node
Gateway
Control Server
Inheritance
Terminal
14
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
3. A Way to Interface with Elements (cont’d)
3. fires
TriggerEvent
Listener
CnxAttempt
Event
7. goes to
4. goes to
8. creates
CnxCompleteEvent
Java
Service
Layer
6. fires
7. goes to
2. goes to
ConnectionFactory
CnxFailEvent
6. fires
ConnectionBinding
5. creates
Connection
TriggerE
vent
1. fires
Service component
Element
Event
Source
Creation and Control of Hybrid Services
Event
15
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Architecture of Our Solution
CT/Si: Subsystem on Terminal for Service #i
CN/Si: Subsystem on Network node for Service #i
CC/Si: Subsystem on Control server for Service #I
CG/Si: Subsystem on Gateway for Service #i
SS:
Service Subsystem
Beans Archive
Service
Creation
Environment
Service Factory
1. Identify service
components
Service Instance
SS
SS SS
2. Download the components
Controller
Java
Service
Layer
ST/
S1
Controller
ST/
S2
SN
/S1
Controller
SC/
S1
SC/
S2
Controller
SG
/S1
Service binding
Service binding
Service binding
Service binding
Terminal
Network Node
Control Server
Gateway
Creation and Control of Hybrid Services
3. Build the
binding
layer
16
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Implementation Test-bed
Java Service Layer
PABX controller
GK controller
Term. controller
H.323
GK
Siemens
Hicom 112
PABX
ISDN BRI
H.323
GW
IP Network
RADVision
Elemedia
H.323
stack
• + Most elements of the test-bed can detect special services, by detecting prefixes in
the numbers dialed
• - APIs existing on the elements are not easily customizable from an application
Creation and Control of Hybrid Services
17
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Voice-Access-to-Email
Java Service Layer
PABX controller
GK controller
Server controller
H.323
GK
Siemens
Hicom 112
PABX
ISDN BRI
H.323
GW
IP Network
Accommodating
server
RADVision
Email
server
Creation and Control of Hybrid Services
18
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Voice-Access-to-Email (cont’d)
• Start retrieving the mails : Email Retriever
• As long as nothing has come
– play waiting message
• Parse the received mail
: User Interaction
: Email Parser
– remove useless header fields (e.g., route information)
– remove useless tags (<FONT>, <BODY>, etc.)
• Convert the parsed file into speech: Microsoft Speech API
(Java wrapper, JNI)
• Play the speech file over the network: Elemedia H.323 stack
• ~30s to read an email
Creation and Control of Hybrid Services
19
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Voice-Access-to-Email (cont’d)
H323 Call
factory
Incoming H.323
messages
Application
User
Interaction
Email
Retriever
Email
Parser
Outgoing H.323
messages
Call instances
Creation and Control of Hybrid Services
Email
Server
Text-tospeech
Converter
20
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Voice-Access-to-W3
H323 Call
factory
Incoming H.323
messages
Application
User
Interaction
Web site
Retriever
HTML
Parser
Outgoing H.323
messages
Call instances
Creation and Control of Hybrid Services
Web
Server
Text-tospeech
Converter
21
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Voice-Access-to-W3: HTML Parser
• Replace a link by an announcement like “Press 234 if you
wanna learn more about this topic”
• Remove applet information
• Remove scripts
• A dedicated language would be a suitable solution but then all
pages would have to be re-written!
Creation and Control of Hybrid Services
22
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Closed User Group
Feature: Confidential information passing between F and C
while in a session with A, B, D and E
Java
Service
Layer
Term.
controller
CUGS controller
H.323
GK
Siemens
Hicom 112
PABX
ISDN BRI
H.323
GW
IP Network
RADVision
A
B
C
Creation and Control of Hybrid Services
D
CUG Server
E
F
23
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Learnings
• The proposed architecture can be used to enhance the
service offerings of current platforms
• To fully take advantage of the architecture, we need
APIs for the platform elements
• Service composability within the architecture has been
illustrated
• Java is a good candidate
Creation and Control of Hybrid Services
24
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Related Work in the Internet
• GeoPlex (AT&T)
– 5 programmable elements:
• Cores: mission-critical
databases and functions
• Hops: e.g., routers
• Gates: entrances to the GeoPlex
network
• Stores: directories, event reports
• Peers: GeoPlex-enabled devices
• Internet-dependent, although
some of the APIs can be re-used
for other elements
Creation and Control of Hybrid Services
Internet
Video
Svc
Store
e Client
Peer
Hop
Gate
e Client
Peer
e Client
Peer
Gate
Gate
Gate
Core
Gate
Gate
Gate
Secure
trusted-domain
boundary
Gate
Hop
Consumer
Network
Hop
Extended
Network
Telephone
Networks
Our solution is more generic and
applicable to all technologies
25
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Related Work in Telecommunications
• Intelligent Network (IN)
– dumb terminals
– services as compositions of functional
building blocks
– service logic controlled by Service Control
Points (SCP)
SCP
SSP
SSP
• no service creation environment
standardized
• building blocks are heavily defined
• limited distribution (functional approach!)
(1) We propose a service creation environment based on a platformindependent language (i.e., Java)
(2) We use an object-oriented technique to find and specify service
components
Creation and Control of Hybrid Services
26
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Related Work in Telecommunications
(cont’d)
• Telecommunications Information
Networking Architecture (TINA)
– goal: enhance the IN with distributed
processing and integrate service
provision and management
• heavyweight connection management
(connection-oriented networks)
• building of service logic not
emphasized
Serv. Sess. Mgr
Net. Cnx Mgr
Net. Elt. Mgr
Net. Elt. Mgr
Computational
object
Our solution provides a simple connection model and a technique to
determine generic service components
Creation and Control of Hybrid Services
27
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Related Work in Telecommunications
(cont’d)
• XBIND (Columbia University, NY)
– same objectives as TINA, but with a
service-centric vision: programmability
of end-systems considered
• ATM-oriented
• lack of a service model
Serv. Sess. Mgr
Device Mgr
Net. Cnx Mgr
Display Mgr
Camera Mgr
Net. Elt. Mgr
Net. Elt. Mgr
(1) Our solution is both past- and future-proof: no specific technology in mind
(2) We provide a service model that helps find service components using an
object-oriented technique
Creation and Control of Hybrid Services
28
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Related Work on Hybrid Services
• Computer-Telephony Integration (CTI)
– goal: be able to place and control telephone calls from a computer
– “IN” for corporate networks
• deployment at the edge of the network, e.g., in enterprise networks: complex
services need also to look into the network
CTI Link
PABX
Creation and Control of Hybrid Services
Our solution enables CTI to
look into the network in order
to implement sophisticated
services
29
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Related Work on Hybrid Services (cont’d)
• PSTN and Internet Interworking (PINT)
– enable a telephone call from an IP
terminal to the PSTN
Web server
Internet (HTTP/CGI)
• data is transported over the PSTN
• no service control from the initiating
IP terminal
PSTN
IP
SCP
SSP
SSP
PSTN
(1) Our solution extends data transport to any network, not only the PSTN
(2) Service control can be performed from the IP network
Creation and Control of Hybrid Services
30
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Summary
• Legacy systems are unlikely to disappear overnight: the future will
be hybrid
• Main contributions
– Thorough assessment of the benefits in integrating Telecoms and Internet
– A service-centric and programmable architecture
– A method for determining service components
– A method for interfacing with service system elements, including existing
networks and mechanisms
• We provide a unified way to interface with existing networks
• Our method enables smooth introduction of new services
Creation and Control of Hybrid Services
31
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Summary (cont’d)
• Future directions
– Inter-provider interface
• how to make service control layers of different operators talk to one
another?
– Management
• how to manage the behavior of a service?
• how to allocate resources for a service and control this allocation?
• how to solve feature interactions?
– Performance
• what do we need to do in order to build a system that performs as
reliably as the PSTN?
Creation and Control of Hybrid Services
32
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
Summary (cont’d)
• Future directions
– Extension to wireless networks
• what are the effects of the characteristics of wireless networks on the
design of the components?
Java Service Layer
BSS
Creation and Control of Hybrid Services
Software Radio
33
Institute for computer
Communications and Applications
Swiss Federal Institute of Technology, Lausanne
Communication Systems Division (SSC)
References
• J. P. Hubaux, C. Gbaguidi, S. Koppenhoefer and J. Y. Le Boudec, “The
impact of the Internet on Telecommunication architectures”, Computer
Networks, Feb. 1999
• C. Gbaguidi, J. P. Hubaux, G. Pacifici and A. N. Tantawi, “Integration of
Internet and Telecommunications: An architecture for hybrid services”,
JSAC, Sept. 1999.
• C. Gbaguidi, J. P. Hubaux, M. Hamdi and A. N. Tantawi, “A programmable
architecture for the provision of hybrid services”, IEEE Comm. Mag., July
1999.
• C. Gbaguidi, S. Znaty and J. P. Hubaux, “Multimedia resources: An
information model and its application to an MPEG2 video codec”, JNSM,
Sept. 1998.
Creation and Control of Hybrid Services
34