Advanced Paradigms for Building Convergent Next
Generation Services. Service Composition and
Service Brokerage in Multimedia Architectures
Dr. Sorin Georgescu
[email protected]
Agenda




NG Service Platform
Multimedia Services Ontology
Service Composition Patterns
Adding Semantics to Service
Composition
 Enhancing the Business Model
through Service Brokerage
Multimedia Service Composition and Service Brokerage
2
Sorin Georgescu
Next Generation Networks Evolution Drivers
Convergence
Societal and Business trends
• Converged devices (Mobile, WLAN,
Internet etc.)  Connectivity
• Internet is becoming a major enabler
of communications
• Converged services  Ease of
use
• Consumers are embracing
computing, mobile and digital
technology in their everyday life
• Converged networks  Reliability,
Security, Reduced OPEX/CAPEX
• Evolution of Business models require
increased levels of personal mobility
• Converged business models 
Increased margins, Avoidance of
twin pitfalls risk
Access Technology Enhancements
• HSPA (High Speed Packet Access) – evolved
WCDMA
• OFDMA (Orthogonal Frequency Division
Multiple Access) – 3GPP LTE, WiMAX, MBWA,
ADSL/VDSL, DVB-T/H etc.
• Spatial Processing – multi-antennas Base
Stations supporting advanced spatial processing
Multimedia Service Composition and Service Brokerage
3
Sorin Georgescu
The Evolution to Multimedia Applications
A Mobile View
Video Movies
Music
Ring tone
Person-to-Content
known usability patterns
Photos
Internet
Streaming
Text/Pictures
Download
Multimedia
Content
HTTP
SMS/MMS
Person-to-Person
dominates traffic growth
Video
Active
phonebook
Image
Social Networking
Text
P2P Calls
Voice
Presence
Push-To-Talk
MMS
SMS
Voice
Multimedia Service Composition and Service Brokerage
4
Sorin Georgescu
IMS – 3GPP Architecture for Convergent Next
Generation Services
• IMS is an open IP-based
architecture using the Client-Server
Network Computing model.
• 3GPP originally specified IMS to
enable real-time multimedia
services over the IP bearer, in GSM
and W-CDMA networks.
• Later, 3GPP2 specified the MMD
architecture for CDMA2000
networks based on IMS. 3GPP2
requirements are part of Common
IMS in IMS release 8.
• The xDSL access, specified by
TISPAN, is integrated into IMS.
• The cable access, specified by
CableLabs in PacketCable 2.0, is
part of IMS release 8.
• Interworking with WLAN was
specified in IMS release 6, while the
mobility with WiMAX has been
addressed in EPC specifications.
Multimedia Service Composition and Service Brokerage
If IMS is not used:
 Multimedia communication at best effort
 Service roaming can be difficult to implement
 Provisioning and charging are service specific
 Compliance with LI requirements can be an issue
5
Sorin Georgescu
IMS Service Routing – the IFCs
Visited A
4
P-CSCF
3
8
Home B
I-CSCF
9
S-CSCF
10
Visited B
Home A
6
S-CSCF
2
7
5
1
IMS AS
HSS
IMS AS
HSS
P-CSCF
• SIP requests in IMS architecture are
always routed to the Home S-CSCF, in
both the originating and terminating
network.
• The S-CSCF uses subscriber’s
Service Profile (downloaded during
registration), to link-in the SIP AS’
which will process the SIP request.
11
IMS Service Routing =
Service Profile based Routing
Multimedia Service Composition and Service Brokerage
• In comparison to IETF SIP Routing
where the originator of SIP request may
specify a preferred path in the Route
header, in IMS the P-CSCF removes
this path and ensures that IMS SIP
Routing is followed.
6
• The Initial Filter Criteria (IFC) within
the Subscriber Profile provide a simple
service logic to decide which AS shall
be linked-in. These rules are of static
nature i.e. they do not change
frequently.
Sorin Georgescu
Limitations of ISC Service Orchestration Model
SIP-AS
SIP-AS
SIP-AS
SIP-AS
Req URI = A
S-CSCF
HSS
SIP-AS
Req URI = B
S-CSCF
HSS
I-CSCF
SIP-AS
I-CSCF
• The application server decides whether to remain
linked-in for the whole session by adding its
address to the Record-Route SIP header.
• Application Servers are unaware of the existence
of other AS', and whether these will be linked-in.
• No service or session state will be passed
between application servers unless they use
proprietary extensions i.e. are co-designed.
• If during call handling procedure an AS retargets
the SIP request by changing the Request URI,
subsequent filter analysis in the S-CSCF is stopped
and the S-CSCF forwards the request towards the
new target without linking-in the other AS’ specified
by IFC.
• Response messages are routed to the AS’s in the
reverse order
1
Multimedia Service Composition and Service Brokerage
2
7
Sorin Georgescu
NG Service Platform
The IMS-based Design
Multimedia Service Composition and Service Brokerage
8
Sorin Georgescu
Multimedia Service Composition and Service Brokerage
9
Sorin Georgescu
IT/Business
Partners
NG Service Platform
Web 2.0
OpenSocial
RSS
Functional Description
IMS & Non-IMS
Enablers
Semantic WS
WS
AJAX
REST
Native API
Service
Discovery
Service
Composition
Parlay X WS
Service
Mediation
Service
Brokerage
Service Composition:
Service Brokerage:
• Invokes the services published by external
Service Providers which are interconnected in a
Service Overlay Network.
• Negotiates with other brokers in the Service
Overlay Network the services which the Service
Composition function will invoke.
• Services can be linked in statically (BPEL
workflows) or dynamically, using their semantic
description (OWL-S)
• Uses context information to bind services
based on dynamic conditions.
• Corresponds to the network-centric composition
model => lower complexity of client implementation.
Service Discovery:
• Publishes local services and performs service
searches in the Service Overlay Network.
Service Mediation:
• Searches can be static (UDDI queries) or
dynamic (UDDI queries with constrains, SWS
Proxy queries).
• Mediates service protocols, data format, identity,
security features, business processes
Multimedia Service Composition and Service Brokerage
10
Sorin Georgescu
Agenda




NG Service Platform
Multimedia Services Ontology
Service Composition Patterns
Adding Semantics to Service
Composition
 Enhancing the Business Model
through Service Brokerage
Multimedia Service Composition and Service Brokerage
11
Sorin Georgescu
Service Modeling using Ontologies
User Interface and Applications
Gruber, 1993:
Trust
“An Ontology is a formal, explicit specification
of a shared conceptualization of a domain.”
Proof
• Formal = unambiguous, machine
understandable, described using a formal
language
RIF/ SWRL
OWL
• Explicit = precise, clarifying the subject
SPARQL
• Conceptualization = abstract representation
of the object of study
RDFS
Encryption
Logic
RDF
XML
• Ontologies consist of a set of axioms which
place constrains on classes of individuals, and
the types of relationships allowed between
them.
URI
Semantic Web Stack
RDF/S = Resource Description Framework / Schema
OWL = Ontology Web Language
SWRL = Semantic Web Rule Language
RIF = Rules Interchange Format
• Can be described in graphical form (ex. RDF,
UML) or logical form (ex. Description Logic,
Rules).
Multimedia Service Composition and Service Brokerage
Unicode
12
Sorin Georgescu
Multimedia Services Ontology
Multimedia
Ontology
Constructs of the ontology:
• Syntactic/semantic description
of offered services (WSDL/OWL)
Services
Sub-ontology
• Description of mediation
functions that can be linked-in at
run-time
Content
Sub-ontology
Security
Sub-ontology
Presence
Sub-ontology
Identity
Sub-ontology
Context
Sub-ontology
• Description of data published
• Multimedia Services Ontology is a
sub-ontology of Multimedia Ontology
which is associated to Multimedia
Communication domain.
• Specification of communication
protocols
• Description of Service
Composition framework. Should
include, if applicable, the
description of the language used
to specify the semantic
composition
Multimedia Service Composition and Service Brokerage
• Multimedia Ontology makes
multimedia services provided by various
Service Providers (Telecom, IT, Web
2.0) interoperable.
13
Sorin Georgescu
Agenda




NG Service Platform
Multimedia Services Ontology
Service Composition Patterns
Adding Semantics to Service
Composition
 Enhancing the Business Model
through Service Brokerage
Multimedia Service Composition and Service Brokerage
14
Sorin Georgescu
Service Oriented Computing (SOC)
 In SOC, applications are statically/dynamically composed using
services deployed in the network. The collaboration model can be
transactional (synchronous), or workflow-based (asynchronous)
Service Oriented
(SOA, Web 3.0)
 SOA is one possible realization framework of SOC. The
communication paradigm typically used in SOA is Web Services
 Web Services are:
− Published (WSDL, OWL, SWSF)
− Deployed
− Discovered (UDDI, WSMO)
− Invoked (SOAP)
Message Driven
(MOM)
Components
(Corba, EJB)
Service composition types:
Service Orchestration = centralized engine which
coordinates composed services according to a set of rules
(workflow specification)
Service Choreography = multiple actors/agents participate
at the implementation of service composition
(orchestration between every pair of choreographers)
Multimedia Service Composition and Service Brokerage
15
Client/Server
Distributed Computing Evolution
Sorin Georgescu
Service Oriented Computing (cont.)
Static Service Composition
User / Service
Profile
Temporal
context
BPEL
Rules
Context
Composition
Engine
User context
Ambient
context
Broker
Discover
UDDI
Service Discovery
and Publication
Publish
Service
Creation
Environment
Multimedia Service Composition and Service Brokerage
Developer
Studio
End User
Studio
16
Sorin Georgescu
Web 2.0 in SOC landscape
Web 2.0
Folksonomy
Podcast
Share & Consume
Share & Consume
Mashup
Wiki
News
Weblog
Tim O’Reilly Web 2.0 definition:
 The API’s exposed are simple enough so
anybody can innovate.
 The Web as a platform
 No more software release cycles. Services are
permanently in beta release.
 Leverages customer data management (mashups) and user interaction model. Hence the
challenge is to own core data (presence, location,
identity, namespaces)
 Syndication of data instead of control. The data
owner is actually paid by the advertisers.
 Multi-device client (ex. Google/Open Handset
Alliance Android mobile platform)
 Promotes service evolution through user
contributions.
 Rich user experience
Multimedia Service Composition and Service Brokerage
17
Sorin Georgescu
Web 2.0 Design Elements
OpenSocial highlights:
Mashup highlights:
• Based on open standards
(XML, HTML, Javascript,
ATOM and REST). Uses
Google Gadgets FW.
• Aggregation of data centric network services using asynchronous interactions (AJAX)
• Implemented with client/server or three-tier architectures:
– Content/API provider: shares mashable data objects typically retrieved using
RSS, ATOM, SOAP, REST interfaces or “Screen Scraping”
• Can be combined with
OpenID (common identity
framework).
– Mashup hosting site (in three-tier architecture): server which aggregates data
using Java Servlets, CGI, PHP or ASP.
• Personal data moves from
site to site.
• Each API addresses one
area: People & Friends,
Activities, Persistence,
General API.
– Mashup client: uses client scripts (JavaScript) or applets to allow support of
Rich Internet Applications (RIA)
• Data may be cached in the client device (SQLite)
• Blogs, Wikis, IM & Chat
Social Applications
• Buddy List, Mashups
Social APIs
• Publishing, Content Sharing
Application
Social Network Diagram
• Open APIs: REST, RSS, JSON,
SOAP, XML
• Widgets: OpenSocial, Web Widgets,
Gadgets, Badges
• Syndication: RSS, ATOM
Multimedia Service Composition and Service Brokerage
18
Service Enablers
Transport / Control Layer
Devices
Sorin Georgescu
Service Composition in Web 2.0
• Compared to BPEL/WSCI developer-centric composition,
Web 2.0 uses ad-hoc composition. The user builds the
composite service “on-the-fly” from data retrieved from the
network. Mobile devices (Smartphones) now have 128MB of
RAM and 620 Mhz CPU, so Web 2.0 clients can now be
mobile.
Data Base
Photo Storage
Application Logic
• Web 2.0 application design is performed by the end user who
in essence, has low programming skills. The service
composition is defined through interaction with a GUI.
Client controlled composition
Email
• Development: client components use APIs to access server
Node Service
Page Logic
API
Templates
Endpoints
Flickr.com
3PP Appl.
data
• Execution: components run on the client and pre-fetch data
from the server
Flicker Architecture
Server controlled composition (early stage)
• Development: the server uses public APIs to link services into
new services
• Execution: the client invokes the server which acts as an
orchestrator
Multimedia Service Composition and Service Brokerage
19
Sorin Georgescu
Flickr Appl
SOA Reference Model
What is SOA:
A paradigm which defines concepts
and general techniques for the
design, encapsulation and
instantiation of reusable business
functions using loosely coupled
service interactions
Visibility
Service
Description
Reachability
Service
Service
Interface
SOA Reference Model:
 Service
Real world
effect
Functionality
 Service description
Interaction
 Interaction
Contract &
Policy
 Contract & Policy
 Visibility
Information
model
Behavior
model
 Execution Context
SOA Service Description Model
 Real world effect
Multimedia Service Composition and Service Brokerage
20
Sorin Georgescu
SOA Service Composition
Appl 1
A p p lic a tio n 1
Client
T
e rm in a l
E n a b lin g
S e rv ic e 1
E n a b lin g
S e rv ic e 2
E n a b lin g
S e rv ic e 3
Routing based on service
identity (equivalent to PSI
routing in IMS)
AS1
A p p lic a tio n 2
AS2
E n a b lin g
S e rv ic e 4
AS3
Service bus functions:
SOA Characteristics
• Supports an asynchronous message
based communication protocol that
uses a common format encoding
scheme (SOAP/XML)
 Services have well defined Service Contracts
• Routes, Translates and can Store
and Forward exchanged messages
• Supports a Discovery mechanism
 Services are encapsulated
 Services share a message bus and messages
exchanged are well documented
 Services can be discovered dynamically
 Services are loosely coupled
 Systems of services are assembled at runtime
Multimedia Service Composition and Service Brokerage
21
Sorin Georgescu
IMS-SOA Architecture
Service Enablers:
Service
Contract
SOA
• Provide functionality which can be used by other
end-user applications (ex. Location Service)
UDDI
SOA AS
• Unaware of the context in which they are used. Only
the consumer service is aware.
Schema
Service Bus
SOAP/XML
• Handles the communication between IMS
Application Servers and the Service Enablers and the
communication with SOA Application Servers.
MLP
SIP
Service Bus
MM7
SB API
SB API
• Optimized for Server-to-Server communication
• Besides providing support for standard open
protocols (ex. SOAP), may provide support for Native
Interface protocols (ex. MLP, MM7, SIP etc.)
GW AS
IMS AS
SB API
Enabler
CSCF
Service Orchestration
Orig. network
JSR 281
• The consumer AS that invokes the Service Enabler
implements the SCIM function. An external Service
Broker may be used as well.
Heterogeneous Service Bus
IMS-SOA Architecture
• IMS Service Enablers are invoked from SOA
domain through the GW AS.
Multimedia Service Composition and Service Brokerage
IMS
22
Sorin Georgescu
Parlay X Web Services
WS-I Basic Profile: WSDL + SOAP
• Parlay X Web Services is an
abstraction of Parlay WS
WS-I Secure Profile: WSDL + SOAP + WS-Security
AS
AS
Parlay-X, Customized interfaces
Trusted Domain
AS
AS
WS Security,
WS-Addressing
Customized
Compound
WS
Parlay-X WS GW
IMS Service
Enablers
Sh
ISC
H.248
HSS
CSCF
Media
resources
• Parlay X WS GW acts as a
Service Broker SCIM
• Enablers which only support
WS-I Basic Profile are
enhanced with additional WS
functionality such as WSSecurity, WS-Policy, WSAddressing
• Services defined so far (17)
cover: call control, messaging
(SMS, MMS), payment,
location, geocoding and
mapping, presence etc.
• Described in WSDL. Service
discovery is based on UDDI.
IMS Core Network
Multimedia Service Composition and Service Brokerage
23
Sorin Georgescu
Agenda




NG Service Platform
Multimedia Services Ontology
Service Composition Patterns
Adding Semantics to Service
Composition
 Enhancing the Business Model
through Service Brokerage
Multimedia Service Composition and Service Brokerage
24
Sorin Georgescu
The Semantic Web
Highlights:
• Information on the Web is machine
understandable => automatic service
discovery, invocation and composition.
• Modeled as a graph where nodes have
semantic descriptions. In Web 1.0 and 2.0
node descriptions are only syntactic.
Service Profile
• Uses ontologies to represent elements of a
domain and their relationships (OWL-S,
SWSF, IRS-III, WSMO)
SWS
Service Model
Service Grounding
User Interface and Applications
Semantic Modeling using OWL-S
Proof
SWS = Semantic Web Service
<item>cat</item>
Logic
Semantic web tag:
<item rdf:about=“http://dbpedia.org/resource/cat”>cat</item>
RIF/
SWRL
OWL
SPARQL
RDFS
Tim Berners-Lee, 2001:
“The Semantic Web looks at applications that enable
transformations, by being able to take large amounts of data and be
able to run models on the fly - whether these are financial models for
oil futures, discovering the synergies between biology and chemistry
researchers in the Life Sciences, or getting the best price and
service on a new pair of hiking boots.”
Multimedia Service Composition and Service Brokerage
25
RDF
XML
URI
Unicode
Semantic Web Stack
Sorin Georgescu
Encryption
Non-semantic web tag:
Trust
SWS Execution Engine
• Performs semantic information
processing and ontology reasoning in
order to:
Composition
Engine
Communication
Handler
Service
Mediation
− discover and select the
matching service
− mediate the data, the protocol
or the business process
associated to service invoked.
Semantic/Ontology
Reasoning
− invoke the service
• Supports both the orchestration and
choreography paradigms
• Data exchanged by SWS is described
as an ontology.
Web Service
Discovery
Matchmaker
• Can be looked at as a SOA
implementation which allows to
add/remove components at run-time.
Resource DB
Semantic Execution Environment
Multimedia Service Composition and Service Brokerage
26
Sorin Georgescu
Semantic Service Composition
Semantic Composition Paradigms:
• Action Based: the Reasoner uses the semantic
description of discovered services to match
requester goal at each composition step (runtime). Execution takes place directly through the
grounding of the services.
• AI Planning: a task list is generated to achieve
the composition objectives i.e. service selection
and flow management. Compensation in case of
failure and replanning is a challenge. Examples of
AI Planning: Conditional Planning, Conformant
Planning, Hierarchical Task Planning (HTP)
• Hybrid (Xplan): Combines guided local search
with graph planning and a light form of HTP to
produce a plan sequence of actions.
Planning Graph
Generation
Enforced Hill
Climbing Engine
PDDXML plan
description
PDDXML Parser
Topology Handler
Connectivity
Graph
Goal
Determination
PDDXML problem,
domain description
Xplan-based Composition
Y
X
X
Y
Z
- Set of actions
- Pos./neg. effects
- Initial state description
- User’s goal
There is not yet a unifying framework to allow
interoperability between intelligent agents /
reasoning engines.
Z
Planning
Sequence
Multimedia Service Composition and Service Brokerage
27
Sorin Georgescu
Agenda




NG Service Platform
Multimedia Services Ontology
Service Composition Patterns
Adding Semantics to Service
Composition
 Enhancing the Business Model
through Service Brokerage
Multimedia Service Composition and Service Brokerage
28
Sorin Georgescu
Service Brokerage in SOC
Why we need Service Brokers:
Service
Consumer
 Users are interested to customize service
interaction model and run-time features based on
context conditions (Ambient Intelligence,
Location, Privacy Preferences etc.)
use
Service
Description
contains
described in
description
Service
Provider
offer
invoke ( )
bindTo ( )
Service
Broker
 Control of the payment model. Users who do
not want adds and are rather looking into QoS
and Security/Privacy, need a Service Broker
function in the network which can negotiate the
service characteristics with multiple service
providers based on user profile.
find ( )
negotiate ( )
Service Broker functions:
User
context
Temporal
context
Ambient
context
• Ranks services offered by the Service Providers
based on service characteristics. It may do this
autonomously (rules based negotiation), or by
interacting with the user
User /
Service
Profile
Broker
• Matches the service interaction model with
context conditions
Context
decisions
• Performs identity and trust brokering
• Performs payment brokering
• Handles synchronization between fine-grained
services
Google business model:
Users accept advertising and profiling in return to free
services. AsSense, AdWorks - advertisers/publishers
or youTube - content providers/users, perform
brokerage at business level.
Multimedia Service Composition and Service Brokerage
29
Sorin Georgescu
IMS Payment Brokerage
G o o d s/S e rvice se le ction a nd ne go tia tion
U se r
• IMS services standardized so far
(MMtel, PoC, Image/Video Share) have
been deployed in the operator domain
as their target are the telecom
communities (mass deployments).
• Separate from these basic services, it
is expected that many new community
specific services (niche services) will
be provided in the near future by
Service Providers. These services use
open communication protocols (instead
of SIP) and do not handle charging of
the user directly. Instead, they use their
business and trust relationship with the
operator, to delegate payment service.
ASP
(M e rch a n t)
T ra n sa ctio n D e ta ils
T ra n sa ctio n C re d en tia ls 1
Funds2
T ra n sa ctio n R e co rd
P a ym e n t
C re d e n tia ls
A u tho rize
T ra n sa ctio n
B ill
S e rvice D e live ry
V a lid a tion
Issu e r
T ra n sa ctio n C re d en tia ls 2
B ro ke r
(A cqu ire r)
Funds1
Payment Model
The roles in Payment Model are similar to
those in Credit Card industry:
− Consumer
• The Payment Brokerage function
facilitates the establishment of the
business relation between 3rd Party
Content/Service Providers and mobile
operators.
Multimedia Service Composition and Service Brokerage
D e live ry
− Merchant = Content Provider who
publishes, supplies and sells content.
− Broker/Acquirer
− Issuer = Mobile Operator. The
Operator uses its existing billing
relationship with the consumer to
charge for content.
30
Sorin Georgescu
Conclusions


Recent deployments of Multimedia and VoIP services in the Telcom and the
Internet domain, have determined a blurring of roles in the value chain while at the
same time enabling new business models.
Next Generation Services Convergence requires:
–
–
–
–
–

The SP Interoperability Middleware has to provide support for:
–
–
–

Implementation of converged devices (multi-access devices)
Support of a multi-access edge network
Unified roaming and session management framework
Development of service enablers
Interoperability between the native Service Platform (SP) and external Service
Overlay Networks
Service Composition and Brokerage
Service Mediation
Service Discovery
Service Platform features like Multimodal Interaction, Interaction Management
based on Ambient Intelligence, Content Management, Brokerage and Management
of Semantic Information are desirable due to their significant impact on service
usability.
Multimedia Service Composition and Service Brokerage
31
Sorin Georgescu
Thank you for your attention!
[email protected]
Multimedia Service Composition and Service Brokerage
32
Sorin Georgescu
Descargar

IMS Convergent Multimedia Services