© 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


Business Example / Need for Protocols


Furniture eProcurement (1)

• 4 Participants:– Retailer– Manufacturer Sales– Manufacturer Procurement– Supplier

• 2 Sub processes:– Selling Process– Procurement Process


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.


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


Motivation and Definition


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


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”)


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


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


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


Business Protocol Standards – Big Picture


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


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


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”


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


(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


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


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


BitsFramesPacketsMinutes

Data link layerUser layerTransport layerApplication layer

PresentationDocumentsInteractionsServices

EDIFACTHTTPRosettaNetebXML

Business Process / Service Definition

Collaboration and Collaboration Agreement


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


Visualizing Business Protocols


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.


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


Graphical representations Protocols II

Source: http://course.wilkes.edu/engineer/discuss/msgReader$3?mode=day

Sequence diagram

Retailer Manufacturer Supplier

Request for Quotaion


Quotation

Quotation

Order

Order

Order Conformation

Order Conformation


Graphical representations Protocols III

Retailer Manufacturer Supplier


(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.


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


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


Examples of current Business Protocols


Standards

Collaboration Agreement

Collaboration

Business Process / Service

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


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.


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 (!)


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.


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


ebXML BPSS III

Source: Kim and Huemer, 2004, “Analysis, Transformation, and Improvements of ebXML Choreographies Based on Workflow Patterns”


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


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:


FIPA Message Structure


FIPA ContractNet Protocol


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


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


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


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.