The Use of
OO-Modelling Principles
(OOM) and
UML Notation to
Define Signalling
RequirementsRaphael J. Schumacher, Rapporteur Q.8/11Swisscom AG, Switzerland
ITUWorkshop
"Use of Description Techniques"
Geneva,23. Nov. 2002
“Use of OOM and UML to define Signalling Requirements”
2ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
A little story about a personal experience in...
attempting to motivate the use ofobject-oriented modelling techniques in SG11
...
advocating the advantages for the experts’ work
...
the attention achieved in the process
...
observations and conclusions
“Use of OOM and UML to define Signalling Requirements”
3ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Contents
1 Introduction– Preamble
– About Signalling Requirements
– The OOM Story in SG11
2 Why OO-Modelling & UML
– OO-Analysis & -Design (OOA/D)
– OO-Modelling (OOM)
– Telecom vs. Computing
3 OOM for BICC Requirements
– Purpose and Benefits
– Existing BICC CS2 Signalling Requirements
– Supplementing BICC Signalling Requirements
4 Results & Conclusion– Reception by the meetings
– Personal observations
– Long-term view
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
4ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
1 Introduction– Preamble
– About Signalling Requirements
– The OOM Story in SG11
2 Why OO-Modelling & UML
– OO-Analysis & -Design (OOA/D)
– OO-Modelling (OOM)
– Telecom vs. Computing
3 OOM for BICC Requirements
– Purpose and Benefits
– Existing BICC CS2 Signalling Requirements
– Supplementing BICC Signalling Requirements
4 Results & Conclusion– Reception by the meetings
– Personal observations
– Long-term view
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
5ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
SG11 Signalling Requirements - what’s this? Question to be answered before protocol development
starts:“What do we expect the particular signalling protocol to do?”
A collection of functional requirements on a signalling protocol that is destined for specific purposes and applications:
– That is, signalling requirements need to identify...– The context of usage (= equal to an applicability statement?)– All the scenarios that need to be applicable
– Hence signalling requirements would contain– Signalling [network] architecture and functional elements– Description of network functions that are needed– Functional elements to be implemented ( != physical elements)
Ideally...Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
6ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
The Proposal for SG11
BICC Capability Set 3 (Bearer Independent Call Control)– BICC is a framework for providing ISDN services over
transport technologies beyond simply TDM: ATM AAL1, AAL2, IP, MPLS.
– In the light of the starting BICC CS3 activity, further ways to improve the modelling techniques for envisaged signalling architecture were seeked.
– This resulted in a contribution brought into WP 2/11 at the SG11 meeting in Mai 2001:
Delayed Contribution D.229 – 2/11Aim: to propagate the idea of using OOM and UML for the development of signalling requirements
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
7ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
1 Introduction– Preamble
– Story line
– About myself and SG11
2 Why OO-Modelling & UML
– OO-Analysis & -Design (OOA/D)
– OO-Modelling (OOM)
– Telecom vs. Computing
3 OOM for BICC Requirements
– Purpose and Benefits
– Existing BICC CS2 Signalling Requirements
– Supplementing BICC Signalling Requirements
4 Results & Conclusion– Reception by the meetings
– Personal observations
– Long-term view
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
8ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Object-Oriented Analysis & Design (OOA/D) A very, very little history:
– late 1980s: OO programming languages (Smalltalk, C++)
– early 1990s: OOA/D techniques (Booch, Rumbaugh, Jacobson, ...)
– late 1990s: joint effort to develop the UML standard; adopted by OMG
OOA&D as conceptual tool was originally directly associated with software development:
– OOA:Analysing a system and its environment, as well as the requirements on the system, seen from a user’s perspective
– OOD:Documentation on the concept, and the design of the implementation (== the inside of the system)
– UML: UML as notation standard; UML tools with the purpose to automatically create program code out of the object-oriented models.
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
9ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Object-Oriented Modelling (OOM)
Simply going beyond the purpose of developing software :– OOA, OOD & UML are description techniques, thus probably
also applicable for other things than software development.
– Meanwhile, modelling is used in many areas, e.g.:– Business engineering: modelling of enterprises in terms of
purpose, processes and organisational entities– Service development: service components and their
associations amongst themselves as well to network capabilities– Database design & data warehouses: data structures,
specifications for data mining and information exchange (XML/DTD)
– Telecom Operations Map (TOM): a framework for a process architecture suitable to telecommunications service providers
– Network Management Systems: managed objects (MIBs)
Why not make profit from OOM & UML in ITU efforts as well?
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
10ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Telecommunication vs. Computing
Telecommunication & computing industry is converging– How will the demarcation line look like in - let’s say - 5 years?
A grey area by best...
– Who will be faced to communication standards in future?– SW developers incorporating telecom modules into vertical
products– Integrators struggling with service convergence telecommunication services won’t remain stand-alone products
– As a consequence, the dominant customers of ITU standards will more and more be...
– software engineers for whom OOM has become everyday practise– service providers which need to cope with the increased
complexity
Telecom services convergence, a long-term business needconsolidating portfolios require clean concepts, interfaces & APIs
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
11ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
1 Introduction– Preamble
– Story line
– About myself and SG11
2 Why OO-Modelling & UML
– OO-Analysis & -Design (OOA/D)
– OO-Modelling (OOM)
– Telecom vs. Computing
3 OOM for BICC Requirements
– Purpose and Benefits
– Existing BICC CS2 Signalling Requirements
– Supplementing BICC Signalling Requirements
4 Results & Conclusion– Reception by the meetings
– Personal observations
– Long-term view
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
12ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
OOM @ BICC: Purpose and Benefits
OOM can be used to:
define processes and information flows
identify relationships between processes and information
increase the degree of reuse (protocol) requirements and components
Benefits:
further refine the scope of BICC capabilities and their protocols
improve the common understanding of terminology
improved documentation of BICC and its evolution (CS1..CS3)
improve quality control and consistency check on protocol designs
trace protocol standardisation (from req’s to test specifications)
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
13ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Existing BICC CS2 Signalling Requirements
Intro
OOM
BICC
Results
Scope of Signalling Requirements
Call ControlSignalling
Bearer ControlSignalling
Signalling Transport Network
BCF-JBCF-RSWN-2
BCF-RSWN-3
CSF-N
ISN-B
BCF-N(z)
Backbone Network
Connection Link
Backbone Network ConnectionsNetwork Bearer Connection (end to end)
CSF-N
BCF-N(v)
ISN-A
BearerInter-working
Function(BIWF)
BCF-RSWN-1
CSF-T
BCF-T(w)
TSN-x
CSF-G
BCF-G(x)
GSN-xCSF-G
BCF-G(y)
GSN-yCSF-C
CMN-x
TE
TE
TE TE
ACN-E
Joint DomainBearer Inter-working
Function (BIWF)
Access Network
BCF-RACN-w
Otherservicesuppliernetworks
CSF-R
BCF-A(a)
Access ControlSignalling
Otherservicesuppliernetworks
Call & Bear Control(CBC) Signalling
“Use of OOM and UML to define Signalling Requirements”
14ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Supplementing BICC Signalling Requirements
1/6Overall Requirements
Use Cases -> helps to refine scopeIntro
OOM
BICC
Results
BICC Network
ISDN service
Multimedia service?
ISDN Network
ISDN Access
(ISDN DSS1 access)
(ISUP)
SIP Network
H.323 Network
??????
“Use of OOM and UML to define Signalling Requirements”
15ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Supplementing BICC Signalling Requirements
2/6Information Flows
Use Case -> overview of scenariosIntro
OOM
BICC
Results
BICC Network
Release ISDNcall/connection
SetupMultimediaconnection
ISDN Network
ISDN Access
(e.g. DSS1)
(ISUP)
SIP Network H.323 Network
???
???
Setup ISDNcall/connection
ReleaseMultimediaconnection
(ISUP)
(e.g. DSS1)
???
???
??????
“Use of OOM and UML to define Signalling Requirements”
16ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Supplementing BICC Signalling Requirements
3/6
BearerNetwork
Call ServiceFunction
(CSF)
BearerInterworking
Function(B-IWF)
0..*1..* 1
ATM BearerNetwork
AAL2 BearerNetwork
IP BearerNetwork
(MPLSBearer
Network)future
0..*
Intro
OOM
BICC
Results
Information Model
Class diagrams -> improve understanding the principle idea of BICC
“Use of OOM and UML to define Signalling Requirements”
17ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Supplementing BICC Signalling Requirements
4/6
Intro
OOM
BICC
Results
Information Model
further
refined
class
diagrams
BearerNetwork
Call ServiceFunction
(CSF)
BearerInterworking
Function(B-IWF)
BICCProtocol
0..*
1..*
1
ATM BearerNetwork
AAL2 BearerNetwork
IP BearerNetwork
MPLSBearer
Network(future)
H.248Protocol
BCP
0..*
Q.2931(ATM BCP)
Q.2630(AAL2 BCP)
IP BCPMPLS BCP
(future)
“Use of OOM and UML to define Signalling Requirements”
18ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Supplementing BICC Signalling Requirements
5/6
Intro
OOM
BICC
Results
Zooming into individual BICC components
“Play it again Sam!”, and:
Bearer Control Function(BICC side only)
Modify Bearer
Release Bearer
BICC Bearer Network
Request BICCBearer
Call Service Function ? BCP ?
BCP
BCPCBC
CBC
? CBC ?
“Use of OOM and UML to define Signalling Requirements”
19ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
EndPoint C
EndPoint B
EndPoint A
External
External
External
O-CSMA
T-CSMB
T-CSMC
CBC
Internal
Internal
Internal
CSF
BIWF
Local Call Instance
TerminationA1
Logical Port-A
TerminationC1
Logical Port-C
TerminationB1
Logical Port-B
CCA
CCA
CCA
BNCBNC
BNC
ContextConnection
BIWF Contr ol Por t
CCU C ontrol Port
(3) (3)
(3)
(2) (2) (2)
(1)
(1)(1)(4)
(4)
(5)
(5)(5)
BearerS ign all in g(optional )
BearerS ign all in g(optional )
Termination States- Null- Loop Back External Signal (loopback)- Loop Back Internal Signal
- Cut-Through Towards Context (Receive)- Cut-Through From Context (Send)- Cut-Through Both (Send / Receive)
Stream Mode
SLP-A SLP-CSLP-BSCF
Supplementing BICC Signalling Requirements
5/6
Intro
OOM
BICC
Results
BIWF (X)
Termination(f)
Termination(h)
Connection(2 party)
Context(3)
Termination(g)
Context(4)
Connection(Hold)
Configuration 3
BIWF-Addr=(Y):BNC-ID=(3)
BIWF-Addr=(W):BNC-ID=(4)
BIWF-Addr=(X):BNC-ID=(5)
BNC
BNC
BNC
Termination(c)
Termination(d)
Termination(e)
Connection(3 party)
Context(2)Configuration 2
BIWF-Addr=(Y):BNC-ID=(2)
BIWF-Addr=(Z):BNC-ID=(4)
BIWF-Addr=(X):BNC-ID=(4)
BNC
BNC
BNC
Termination(a) Termination(b)
Connection(2 party)
Context(1)Configuration 1
BIWF-Addr=(Y):BNC-ID=(1) BIWF-Addr=(Y):BNC-ID=(4)
BNCBNC
Local Call Instance
Local Call Instance
Local Call Instance
And there’d be much more to be modelled!
“Use of OOM and UML to define Signalling Requirements”
20ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
1 Introduction– Preamble
– Story line
– About myself and SG11
2 Why OO-Modelling & UML
– OO-Analysis & -Design (OOA/D)
– OO-Modelling (OOM)
– Telecom vs. Computing
3 OOM for BICC Requirements
– Purpose and Benefits
– Existing BICC CS2 Signalling Requirements
– Supplementing BICC Signalling Requirements
4 Results & Conclusion– Reception by the meetings
– Personal observations
– Long-term view
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
21ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Reception by the Meeting (of WP 2/11)Achieved Interest
Remarkable interest shown by SG11 management
Moderate interest seen from participants progressing work
Gap between S.P. and Suppliers
Statement of Scepticism
Nice, but do we really need this?
Learning curve steep enough?
Return on investment?
UML not a bit too formal?
Possible Reasons for Spectisism
(Past) Experiences with Notations
SDL:Widely adopted within SG11 (protocol standards, typically specifying the state machines), but applied in the right way?
TTCN:ratio of sophistication vs. value was not perceived to be very promising to individuals
Little popularity of concept work
“With IP, everything is easier”
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
22ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Personal Observations
“Contemporary” factors
Time pressure->get out standards fast
Little resources available->reduce efforts to the
minimum
Increased Fluctuation->people change,
know-how changes...
Current quality control system-> iterative approach: changes
to standards as implementers discover imperfect parts
“Hidden” factors
Conceptual work– generally having a hard time
– benefits not convincing enough
ITU “hidden law”:A playground for different parties with particular interests. Lobbying e.g. to...
– advocate a specific solution
– slow down progress of work?
->often, full transparency is not necessarily desired
->poisons top down approaches
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
23ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Personal Long-term Views
Think positive!
Complexity in telecom will continue to increase
->a common understanding of technical and conceptual issues is indispensable
Parties with particular interest in transparency:
– Governments:regulation, lawful interception
– Service Providers:service convergence challenge, cope with network complexity
Summing up
Need for conceptual work– still an indisputable necessity
– adoption of new techniques takes a lot of time-> patience with optimism
Factors for success/failure:– on actual participation
(parties)
– market pressures (competition)
– the mood of telecom business
Better days will be coming
again
Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
24ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Thank you!
...and enjoy your stay in Switzerland
...despite the *?+!%ç&*/ weather!
coffee breaknow?
psst!
“Use of OOM and UML to define Signalling Requirements”
25ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Supplemental
BACKUP
“Use of OOM and UML to define Signalling Requirements”
26ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Links & Book References 1/2
OOA/D http://www.sdmagazine.com/articles/1999/0006/0006a/0006a.htm “Building Object Applications That Work: Your Step-By-Step
Handbook for Developing Robust Systems with Object Technology” by Scott W. Ambler (Cambridge University Press, 1998)
OOM http://www.ambysoft.com/eCommerceArchitecture.html http://www.sdmagazine.com/articles/1999/0004/0004o/0004o.htm “Business Engineering With Object Technology” by David Taylor
(John Wiley and Sons, 1995) “Enterprise Modelling with UML” by Chris Marshall (Addison-
Wesley, Object Technology series, 1999)Intro
OOM
BICC
Results
“Use of OOM and UML to define Signalling Requirements”
27ITU Workshop on "Use of Description Techniques"Geneva, 23 November 2002
Links & Book References 2/2
UML
http://www.omg.org/uml
http://www.rational.com/uml
“The Unified Modeling Language Reference Manual” by Grady Booch, James Rumbaugh, and Ivar Jacobson (Addison-Wesley, Object Technology Series, 1999)
“The Unified Modeling Language User Guide” by Grady Booch, James Rumbaugh, and Ivar Jacobson (Addison-Wesley, Object Technology Series, 1999)
Intro
OOM
BICC
Results