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Transcript of © 2005-2006 The ATHENA Consortium. Jörg Ziemann, DFKI Timo Kahl, DFKI Business Protocols –...
© 2005-2006 The ATHENA Consortium.
Jörg Ziemann, DFKI
Timo Kahl, DFKI
Business Protocols –
Concepts and Techniques
2© 2005-2006 The ATHENA Consortium.
Course Structure
1. Business Example
2. Motivation and Definition
3. Business Protocol Standards – Big Picture
4. Visualizing Business Protocols
5. Examples of current Business
Protocols
© 2005-2006 The ATHENA Consortium.
Business Example / Need for Protocols
4© 2005-2006 The ATHENA Consortium.
Furniture eProcurement (1)
• 4 Participants:– Retailer– Manufacturer Sales– Manufacturer Procurement– Supplier
• 2 Sub processes:– Selling Process– Procurement Process
5© 2005-2006 The ATHENA Consortium.
Furniture eProcurement (2)
Interior Decoration Project
MANUFACTURER
RETAILER
SUPPLIER
R1: Request for Quotation
R2: Quotation
R3: Order
R4: Order Confirmation
M1: Request for Quotation
M2: Quotation
M3: Order
M4: Order Confirmation
• In general:- A business process is defined as
a goal oriented, value creating sequence of activities. In a collaborative business process, these activities are executed by more than one enterprise.
- A business protocol specifies how messages have to be exchanged between different parties participating in a collaborative process.
6© 2005-2006 The ATHENA Consortium.
What requirements should business protocols fulfill?
• From ATHENA users (excerpt)– Enacting View Processes, Monitoring and Controlling
of protocols, Event notification, Compliance with existing solutions Cp. ATHENA Deliverable A7.1 (2006)
• Generic requirements– Re-usability– Flexibility– Self Healing– Ad Hoc Processes – Precise meta-model, machine-interpretable– “Semantic annotation” of data– Visualization
© 2005-2006 The ATHENA Consortium.
Motivation and Definition
8© 2005-2006 The ATHENA Consortium.
Need for business protocols?
• A protocol is a precise description of a possible message exchange.
• A business protocol precisely describes message exchanges occurring within a cross-organizational business process.– Of Interest are application layer messages. E.g. not “Transmit
message chunk X to Router Y” but “Send RfQ to Organizational Unit Z”
• Why do we need business protocols?– basis for interoperability– formal description of message exchanges
• When don’t we need them?– Like other form of process automation, automating interacting
processes makes only sense if they are repeated frequently
9© 2005-2006 The ATHENA Consortium.
Various Definitions of protocols
• A protocol consists of rules which have to be obeyed by communicating processes (Tannenbaum and van Steen, 2002, “Distributed Systems. Principles and Paradigms”)
• A business protocol specifies the potential sequencing of messages exchanged by one particular partner with its other partners to achieve a business goal. I.e. a business protocol defines the ordering in which a particular partner sends messages to and expects messages from its partners based on actual business context (Leymann and Roller, 2004, “Modeling Business Processes with BPEL4WS”)
• A conversation protocol is “… a specification of a set containing all correct and acknowledged conversations”– a conversation represents “sequences of operations (i.e., message
exchanges) that could occur between a client and a service as part of the invocation of a Web service” (Alonso, Casati, Kuno and Machiraju, 2004, „Web Services – Concepts, Architectures and Applications”)
• Web Service Choreography is “... a multi-party contract that describes from a global view point the external observable behavior across multiple clients in which external observable behavior is defined as the presence or absence of messages that are exchanged between a Web Service and it's clients” (Austin, Barbir, Peters, Ross-Talbot, 2004, „Web Services Choreography Requirements-W3C Working Draft 11 March 2004”)
10© 2005-2006 The ATHENA Consortium.
Content to be displayed by business protocols
• What information needs to be transmitted in cross-organizational scenarios?– Data, Process (Control), Function, Output, Organization
Pu
blic
Pro
cess
O
rga
niza
tion
A
Adapt organi-zational
responsibilites
Organization A
Adapt Data Stuctures
Adapt Goodsand Services description
- -
-
-
Output
Control Function
Organization
Organization B
Adapt interaction sequences
Data
Pu
blic Proce
ss O
rga
nization B
- -
-
-
Output
Control Function
Organization
Data
11© 2005-2006 The ATHENA Consortium.
Content to be displayed by business protocols II
Source: Bernauer, Kappel and Kramler, 2003, „Comparing WSDL-Based and ebXML-Based Approaches for B2B Protocol Specification“
• Functional aspects,
• Operational aspects,
• Informational aspects,
• Behavioral aspects,
• Organizational aspects,
• Transactional aspects ,
• Causal aspects and
• Historical aspects
12© 2005-2006 The ATHENA Consortium.
QuestionsNo Question Option A Option B Option C Option D
1.1
What are important aspects of Tannenbaum and van
Steen’s definition of protocols:
A protocol consists of rules
The processes are programs that are executed by one
system
The definition focuses on the viewpoint of
one partner
Communicating processes have to obey the rules
1.2What is specific for a
conversation protocol?
Is a specification of set containing all correct and acknowledged
conversations
A conversation represents
“sequences of operations”
Is a multi-party
contract
The Operations are as part of the
invocation of a Web service
1.3What is specific for a Web Service Choreography?
Focuses on the presence or absence of messages between a Web Service and it's
clients
Is a multi-party contract
Describes from a global view point the external observable
behavior across multiple clients
Multiple clients are generally Web Services
1.4What kind of organizational
dimensions a business process can consist of?
Function, organization, data, output and
control
Only output and organization
Function, organization, data, output and process
Only data
1.5Which content should be
displayed by business protocols?
Historical aspectsOrganizational
aspectsFunctional aspects
Operational aspects
1.6Why do we need business
protocols?Internal Process
automation Basis for
interoperability
For automating interacting processes that are not repeated
frequently
Formal description of
message exchanges
© 2005-2006 The ATHENA Consortium.
Business Protocol Standards – Big Picture
14© 2005-2006 The ATHENA Consortium.
Protocols stem from various areas
Web Service Collaboration
Protocols
Pi- Calculus
Mulit-Agent-Systems
Speech Act Theory
Agent Communication
Languages
Network Protocols
E-Business Protocoll Suites
Behavioural Interfaces
Choreo-graphies
HTTP, UDP, TCP, IP
Reliability, Security on
Network level
RossettaNet, ebXML,
EDIFACT
WS-Coordination, WS-Reliability,
WS-atomic-Transaction
15© 2005-2006 The ATHENA Consortium.
What is a protocol stack?
• A group of complementary protocols • Enables modularization, e.g. each protocol can focus on
one distinguished objective• Usual Architecture:
– Lowest level deals with physical interaction of hardware• Every higher level adds more features
– User applications deal with top layer
Illustration from http://en.wikipedia.org/wiki/Internet_Protocol
16© 2005-2006 The ATHENA Consortium.
A classic protocol stack: ISO/OSI
• Open Systems Interconnection Reference Model, 7 Layers
Layer Data unit Function Example Standards
Application
Data
Network process to application HTTP, SMTP, FTP
Presentation Data representation and encryption ASCII, MPEG
Session Interhost communicationSession related parts in UDP, TCP
Transport SegmentsEnd-to-end connections and reliability
TCP, UDP
Network PacketsPath determination and logical addressing (IP)
IP, IPSec
Data link Frames Physical addressing (MAC & LLC) PPP (Point to Point Protocol)
Physical BitsMedia, signal and binary transmission
DSL
Cp. Zimmermann, 1980, „OS1 Reference Model-The IS0 Model of Architecture for Open Systems Interconnection” and Kurose, Ross, 2001, “Computer Networking: A Top-Down Approach Featuring the Internet”
17© 2005-2006 The ATHENA Consortium.
Before the Web Services Stack: EcoFramework
Source: Chen et al., eCo Architecture for Electronic Commerce Interoperability, 1999, http://www2.sims.berkeley.edu/academics/courses/is290-4/s03/readings/ecoframework.pdf
18© 2005-2006 The ATHENA Consortium.
(One) Web Service Protocol Stack
Orchestration
Quality of Service
Description
Messaging
Transport
BPEL
WS - Coordination
WSDL
XML, SOAP
TCP/IP, HTTP
WS - Transaction WS -
Security
Choreography WSCI , WS - CDL UDDI
19© 2005-2006 The ATHENA Consortium.
Classification Categories
• Collaboration Agreement: – agree on a document standard and how to implement it
• Collaboration: – exchange information and data between organisations, specified
e.g. in protocols, or cross-organisational business processes
• Business Process / Service Definition: – define organisation-internal business processes and business
services
• Information Definition: – define business documents and data models
• Infrastructure Services: – specify infrastructure necessary to model and exchange business
documents
20© 2005-2006 The ATHENA Consortium.
Business Protocol Standards - Overview
Collaboration Agreement
Collaboration
Business Process / Service
Definition
Information Definition
Infrastructure Services
ebXML CPPA
Implementation Guide
Variant Problem
ebXML BPSS
ebXML CCTS
RosettaNet PIPs
RosettaNet Data
Dictionary + schemas
STEP
EDI STAR OAGI WS-CDL
WS-BPEL XPDL
EDI STAR OAGI UML UBLstandard product
attributes
W3C transport protocols (HTTP,
SOAP, etc.)WSDL Discovery IEEE FIPA
OGSA, OGSI
21© 2005-2006 The ATHENA Consortium.
BitsFramesPacketsMinutes
Data link layerUser layerTransport layerApplication layer
PresentationDocumentsInteractionsServices
EDIFACTHTTPRosettaNetebXML
Business Process / Service Definition
Collaboration and Collaboration Agreement
Information Definition
Transport
E-Business Protocol Suites
Agent
Communication Languages
Network
Protocols
Are these data units part of the ISO/OSI model?
1.5
Is this a layer of a protocol stack?
1.3
Is this a layer of the EcoFramework?
1.4
What is an E-Business Protocol Suite?
1.2
What is a Classification category for standards
1.6
Web Service Collaboration
Protocols
From which areas stem protocols?
1.1
Option DOption COption BOption AQuestionNo
© 2005-2006 The ATHENA Consortium.
Visualizing Business Protocols
23© 2005-2006 The ATHENA Consortium.
Different ways to describe interactions
• Orchestration (=Private process, Executable Process, Programming in the large)
– Organization A describes for internal use which services it invokes within one internal business process
– Various Services are embedded in a control flow constituting an executable end-to-end process
• Behavioral Interface (= View Process, Public Process, Abstract Process, Protocol, Choreography Description)
– Organization A describes for one or more partners which message it expects and will send out within a specific cross-organizational business process
– Interface to the outside-world which extracts only that kind of information which is necessary for the interaction with one or more potential partners.
– Abstracts information from a private process
• Global Process (= Choreography Description, Protocol)– Organization A, B, and C describe which messages they mutually exchange within
a specific cross-organizational business process– Describes interactions from a neutral perspective, capturing all allowed
interactions between all partners.
24© 2005-2006 The ATHENA Consortium.
Graphical representations Protocols
Source: http://course.wilkes.edu/engineer/discuss/msgReader$3?mode=day
• Various diagram types can be used to display protocols, e.g.– State machine
• View Process, Global Process
– Sequence Diagram• View Process, Global Process• Not recommended for complex interactions
– Collaboration Diagram• Global Process
– Activity Diagram • View Process, Global Process
25© 2005-2006 The ATHENA Consortium.
Graphical representations Protocols II
Source: http://course.wilkes.edu/engineer/discuss/msgReader$3?mode=day
Sequence diagram
Retailer Manufacturer Supplier
Request for Quotaion
Request for Quotaion
Quotation
Quotation
Order
Order
Order Conformation
Order Conformation
26© 2005-2006 The ATHENA Consortium.
Graphical representations Protocols III
Retailer Manufacturer Supplier
Request for Quotaion
(to manufacturer)Request for
Quotaion(to supplier)
Quotaion(to manufacturer)
Quotaion(to retailer)
Order(to manufacturer)
Order(to supplier)
Order Conformation
(to manufacturer)
Order Conformation
(to retailer)
Activity diagram(global process)
Collaboration diagram (global process)
1: Request for Quotaion
4: Quotation
8: Order Confirmation
5: Order
2: Request for Quotaion
3: Quotation
6: Order
7: Order Confirmation
Manufacturer
Retailer Supplier
Swim lanes can be seen as behavioral Interfaces.
27© 2005-2006 The ATHENA Consortium.
EPC for protocol modeling
Check Credit history
XOR
Volume < 10
Volume >= 10
Send discount
offer
Send regular priice
XOR
Quotation created
Solvency checked
Check Sales Volume
Request for Quote
RFQ received
Quotation
Discount offer
Financial Data
ERP System
Private Process View Process 2
Quotation handling
1 Request for
Quote
Quotation handled
Quotation handling 2
Quotation handled
RFQ received
Quotation
XOR
Volume < 10 m .
Volume > = 10 m .
Send discount
offer
Send regular price
XOR
Quotation created
Check Sales Volume
Quotation handling 1
Request for
Quote
Quotation handled
RFQ received
QuotationDiscount offer
View Process 1
28© 2005-2006 The ATHENA Consortium.
No Question Option A Option B Option C Option D
1.1What kind of scenarios do different diagrams permit?
Collaboration diagrams only allow the
realization of one scenario
Collaboration diagrams permit more complex scenarios than
activity diagrams
Activity diagrams are able to specify various valid sequences
Activity diagrams allow only one valid sequence
1.2 A private processIs an Interface to the outside-world
Describes interactions from a neutral perspective
Can be executedDescribes for
internal use which service it envokes
1.3What is a Behavioral
Interface?Private
processView Process, Public Process
Abstract Process and Protocol
Choreography Description
1.6What kind of diagrams can be used in order to display
a protocol?
State
machineSequence Diagram
Collaboration
Diagram
Activity
Diagram
© 2005-2006 The ATHENA Consortium.
Examples of current Business Protocols
30© 2005-2006 The ATHENA Consortium.
Standards
Collaboration Agreement
Collaboration
Business Process / Service
Definition
Information Definition
Infrastructure Services
ebXML CPPA
Implementation Guide
Variant Problem
ebXML BPSS
ebXML CCTS
RosettaNet PIPs
RosettaNet Data
Dictionary + schemas
STEP
EDI STAR OAGI WS-CDL
WS-BPEL XPDL
EDI STAR OAGI UML UBLstandard product
attributes
W3C transport protocols (HTTP,
SOAP, etc.)WSDL Discovery IEEE FIPA
OGSA, OGSI
31© 2005-2006 The ATHENA Consortium.
RosettaNet PIPs I
RosettaNet, a subsidiary of GS1 US™:• Non-profit consortium developing standards for an XML-based e-
business framework.• Covers the entire spectrum of types of standards, from infrastructure
services, at the lowest level, to collaboration agreements at the highest level.
• At the collaboration level, RosettaNet describes collaborative processes as Partner Interface Processes® (PIP®).
• A PIP® choreography describes a cross-organizational business process between two partners – Describes protocols informally using text and diagrams.
32© 2005-2006 The ATHENA Consortium.
RosettaNet PIPs II
• Contents of a PIP (until 2003, DTD based)– DTD Description of message– Message Guidelines that describe additional details and
constraints that DTD could not describe– Business activities and their sequence as an UML activity
Diagram– Quality of Service attributes
• Problems in implementing RosettaNet PIPs (Study from 2001, Damodaran, S., (2005): RosettaNet: Adoption Brings New Problems, New Solutions)
– Ambiguity, incompleteness, and inconsistencies in PIP specifications
– Lack of reuse across PIP specifications– Too many options in action message contents
• DTD approach was replaced by XSD– Automatic transformation of UML Activity to XML format– Description of Business Process with ebXML BPSS (!)
33© 2005-2006 The ATHENA Consortium.
ebXML BPSS I
• ebXML started in 1999 – initiative of OASIS and the United Nations/ECE agency CEFACT
Cp. http://www.ebxml.org/geninfo.htm– Motivation
• BPM needed to be stronger• Cheap solutions for SMEs
• Original project delivered five layers of data specification in form of XML standards
– Business processes – Collaboration protocol agreements – Core data components – Messaging – Registries and repositories
• Initiative has developed a set of standards specifically targeted at the specification of B2B protocols
– In parallel to Web Services. Vendor support for ebXML, however, is not as strong as for Web Services.
– ebXML-based and the WSDL-based approaches are not compatible Bernauer, M.; Kappel, G.; Kramler, G.: Comparing WSDL-Based and ebXML-Based Approaches for B2B Protocol Specification, ICSOC'03, Trento, 2003.
34© 2005-2006 The ATHENA Consortium.
ebXML Phases
• General Preparation– Describe Global Process as BPSS (Business Process Specification Schema)
• XML based description of business collaborations• Contains references to further ebXML core components, e.g. documents• Contains parameters necessary for runtime, e.g. execution of processes• Closely related to UMM BTV• Global Process, roles of all parties
– Save BPSS in Registry• Initiation
– CPP (Collaboration Protocol Profile)• Requirements (View Process) of each Partner• Document types, Signatures etc.• What does a partner offer?
– Which Interfaces, Business Processes, Contact Information– E.g. which BPSS does partner XY support?
• Negotiation– CPA (Collaboration Protocol Agreement)
• Concrete Details• Pattern for execution
• Execution– Exchange documents
35© 2005-2006 The ATHENA Consortium.
ebXML BPSS III
Source: Kim and Huemer, 2004, “Analysis, Transformation, and Improvements of ebXML Choreographies Based on Workflow Patterns”
36© 2005-2006 The ATHENA Consortium.
FIPA (Foundation for Intelligent Physical Agents)
• Member of the Standards Committee of the IEEE Computer Society
• Promotion of technologies and interoperability specifications that facilitate the end-to-end communication and work of intelligent agent systems in modern commercial and industrial settings.
• Provides specifications for:– Abstract Architecture– Agent Communication and Protocols– Agent Message Transport– Applications
37© 2005-2006 The ATHENA Consortium.
FIPA-Specifications
One of the most relevant specifications for agent
• Message-exchange sequences• Set of basic actions (structure +
semantic)• Message definition:
– Structure– Representation– Transportation details
Interactions Protocols
Speech Acts
FIPA ACL Message
Transport Message
Message Contents Representation
Message Envelope Representation
FIPA Communication Specification Stack:
38© 2005-2006 The ATHENA Consortium.
FIPA Message Structure
39© 2005-2006 The ATHENA Consortium.
FIPA ContractNet Protocol
40© 2005-2006 The ATHENA Consortium.
WS-BPEL I
• Formerly BPEL4WS: Business Process Execution Language for Web Services– Founded 2002 by IBM, BEA und Microsoft et al.
• A „Programming Language“ in XML– Programming in the large– BPEL mainly delivers controll flow to connect various Web
Services– Builds on WSDL, uses XMLSchema, XPath and WS-Addressing– Block structured (inheritance from XLANG) and Graph structured
(from WSFL)– Roles of parties involved– No predefined messages
41© 2005-2006 The ATHENA Consortium.
WS-BPEL II
• Two kind of processes in BPEL– Executable processes
• Orchestration• Programming in the large• Private Process
– Abstract processes• Choreography• Behavioral Interface, Process Stub, View Process, Protocol
– No global processes
• Structured and Basic Activities– Structured
• Sequence, while, switch, flow, pick
– Basic• Assign, invoke, receive, reply, throw, wait, empty
42© 2005-2006 The ATHENA Consortium.
QuestionsNo Question Option A Option B Option C Option D
1.1 RosettaNet
Is aNon-profit consortium developing standards for an XML-
based e-business framework
Builds on WSDL, uses XMLSchema,
XPath and WS-Addressing
Describes collaborative
processes as Partner Interface Processes
Covers the entire spectrum of types of
standards
1.2 Is this a PIP content?DTD Description of
message
Quality of Service
attributes
A Business Process
Specification Schema
ebXML
1.3ebXML provides data
specifications for?
Business processes and core data components
View Processes Collaboration protocol agreements
Registries and repositories
1.4Business Process
Specification Schema (BPSS)
Is a XML based description of business collaborations
Closely related to UMM BTV
Contains parameters necessary for runtime
Contains references to further ebXML core components
1.5FIPA (Foundation for
Intelligent Physical Agents) provides specifications for?
Applications and Abstract Architecture
Agent Communication and Protocols
Scenario descriptions of CBPS
Agent Message Transport
1.6Business Process Execution Language for Web Services
Is a programming Language in XML
Mainly delivers control flow to
connect various Web Services
Builds on WSDL, uses XMLSchema,
XPath and WS-Addressing
Is block structured and graph structured
43© 2005-2006 The ATHENA Consortium.
Sources cited• Vitteau, B.; Huget, M.: Modularity in Interaction Protocols. In: Digum, F.: ACL 2003, LNAI 2922, pp.
291-309.• Tannenbaum, A.; van Stehen, M.: Distributed Systems - Principles and Paradigms, Prentice Hall,
2002. • Leymann, F.; Roller, D.: Modeling Business Processes with BPEL4WS. In: Nüttgens, M.; Mendling,
J.: XML4BPM 2004 - XML Interchange Formats for Business Process Management. 1st Workshop of German Informatics Society e.V. (GI) in conjunction with the 7th GI Conference “Modelierung 2004“, Marburg 2004, pp. 7-24.
• Alonso, G.; Casati, F.; Kuno, H.; Machiraju, V.: Web Services – Concepts, Architectures and Applications. Springer, Berlin 2004.
• Austin, D.; Barbir, A.; Peters, E.; Ross-Talbot, S.: Web Services Choreography Requirements-W3C Working Draft 11 March 2004. http://www.w3.org/TR/2004/WD-ws-chor-reqs-20040311/, online: 2004-05-30.
• Bernauer, M.; Kappel, G.; Kramler, G.: Comparing WSDL-Based and ebXML-Based Approaches for B2B Protocol Specification, ICSOC'03, Trento, 2003.
• Zimmermann, H.: OS1 Reference Model-The IS0 Model of Architecture for Open Systems Interconnection. IEEE Transactions on Communications, Vol. COM-28, No. 4, 1980.
• Kurose, J.; Ross, K.: Computer Networking: A Top-Down Approach Featuring the Internet. Addison-Wesley, 2001.
• Kramler, G.; Kapsammer, E.; Retschitzegger, W.; Kappel, G.: Towards Using UML 2 for Modelling Web Service Collaboration Protocols. In Proc. First Interoperability of Enterprise Software and Applications, Geneva, Switzerland, February 2005. http://www.big.tuwien.ac.at/research/publications/2005/0305.pdf.
• Kim, J.-H.; Huemer, C.: Analysis, Transformation, and Improvements of ebXML Choreographies Based on Workflow Patterns. LNCS, Springer, 2004.