ITU
Workshop
"Use of
Description
Techniques"
Geneva,
23. Nov. 2002
The Use of
OO-Modelling Principles (OOM) and
UML Notation to
Define Signalling Requirements
Raphael J. Schumacher, Rapporteur Q.8/11
Swisscom AG, Switzerland
“Use of OOM and UML to define Signalling Requirements”
A little story about a personal experience
in...
attempting to motivate the use of
object-oriented modelling techniques in SG11
...
advocating the advantages for the experts’ work
...
the attention achieved in the process
...
observations and conclusions
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
2
“Use of OOM and UML to define Signalling Requirements”
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
Intro
OOM
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
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
3
“Use of OOM and UML to define Signalling Requirements”
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
Intro
OOM
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
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
4
“Use of OOM and UML to define Signalling Requirements”
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
Intro
OOM
BICC
Results
– Signalling [network] architecture and functional elements
– Description of network functions that are needed
– Functional elements to be implemented ( != physical elements)
Ideally...
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
5
“Use of OOM and UML to define Signalling Requirements”
The Proposal for SG11
BICC Capability Set 3 (Bearer Independent Call Control)
Intro
– 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 – 2/11
Aim: to propagate the idea of using OOM and UML for the
development of signalling requirements
OOM
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
6
“Use of OOM and UML to define Signalling Requirements”
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
Intro
OOM
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
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
7
“Use of OOM and UML to define Signalling Requirements”
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:
Intro
OOM
BICC
Results
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.
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
8
“Use of OOM and UML to define Signalling Requirements”
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.:
Intro
OOM
BICC
Results
– 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?9
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
“Use of OOM and UML to define Signalling Requirements”
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...
Intro
OOM
BICC
Results
– software engineers for whom OOM has become everyday
practise
– service providers which need to cope with the increased
complexity
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
 Telecom services convergence, a long-term business need
10
“Use of OOM and UML to define Signalling Requirements”
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
Intro
OOM
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
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
11
“Use of OOM and UML to define Signalling Requirements”
OOM @ BICC: Purpose and Benefits
OOM can be used to:
Benefits:
 define processes and
information flows
 further refine the scope of BICC
capabilities and their protocols
 identify relationships between
processes and information
 improve the common
understanding of terminology
 increase the degree of reuse
(protocol) requirements and
components
 improved documentation of
BICC and its evolution
(CS1..CS3)
 improve quality control and
consistency check on protocol
designs
Intro
OOM
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
 trace protocol standardisation
(from req’s to test
specifications)
12
“Use of OOM and UML to define Signalling Requirements”
Existing BICC CS2 Signalling
Requirements
Signalling Transport Network
TE
Other
service
supplier
networks
Other
service
supplier
networks
Call Control
Signalling
Bearer Control
Signalling
Call & Bear Control
(CBC) Signalling
TE
Access Control
Signalling
Access Network
TSN-x
ISN-A
CSF-N
TE
BCF-N
(v)
Bearer
Inter-working
Function
(BIWF)
GSN-x
CSF-T
SWN-1
BCF-R
BCF-T
(w)
Backbone
Network
Connection
Link
Intro
CSF-G
SWN-2
BCF-R
BCF-G
(x)
CMN-x
GSN-y
CSF-C
CSF-G
BCF-G
(y)
BCF-J
SWN-3
BCF-R
ACNE
CSF-R
ISN-B
CSF-N
BCF-N
(z)
ACN-w
BCF-R
TE
BCF-A
(a)
Joint Domain
Bearer Inter-working
Function (BIWF)
Backbone Network Connections
Network Bearer Connection (end to end)
OOM
Scope of Signalling Requirements
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
13
“Use of OOM and UML to define Signalling Requirements”
Supplementing BICC Signalling
Requirements
Overall Requirements
1/6
BICC Network
Multimedia service
?
(ISUP)
ISDN service
ISDN Network
(ISDN DSS1 access)
???
???
H.323 Network
Intro
OOM
ISDN Access
SIP Network
Use Cases -> helps to refine scope
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
14
“Use of OOM and UML to define Signalling Requirements”
Supplementing BICC Signalling
Requirements
Information Flows
2/6
BICC Network
Setup
Multimedia
connection
Setup ISDN
call/connection
(ISUP)
Release
Multimedia
connection
Release ISDN
call/connection
(ISUP)
ISDN Network
(e.g. DSS1)
???
???
???
???
???
(e.g. DSS1)
ISDN Access
SIP Network
???
H.323 Network
Intro
OOM
Use Case -> overview of scenarios
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
15
“Use of OOM and UML to define Signalling Requirements”
Supplementing BICC Signalling
Requirements
3/6
Information Model
Call Service
Function
(CSF)
1..*
0..*
Bearer
Interworking
Function
(B-IWF)
ATM Bearer
Network
0..*
AAL2 Bearer
Network
1
IP Bearer
Network
Bearer
Network
(MPLS
Bearer
Network)
future
Intro
OOM
Class diagrams -> improve understanding the principle idea of BICC
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
16
“Use of OOM and UML to define Signalling Requirements”
Supplementing BICC Signalling
Requirements
Call Service
Function
(CSF)
BICC
Protocol
4/6
1..*
Information Model
H.248
Protocol
0..*
Bearer
Interworking
Function
(B-IWF)
0..*
BCP
further
1
refined
Bearer
Network
Q.2931
(ATM BCP)
Q.2630
(AAL2 BCP)
IP BCP
MPLS BCP
(future)
class
Intro
OOM
diagrams
ATM Bearer
Network
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
AAL2 Bearer
Network
IP Bearer
Network
MPLS
Bearer
Network
(future)
17
“Use of OOM and UML to define Signalling Requirements”
Supplementing BICC Signalling
Requirements
5/6
Zooming into individual BICC components
Bearer Control Function
(BICC side only)
Request BICC
Bearer
CBC
BCP
CBC
BCP
Release Bearer
Call Service Function
? CBC ?
? BCP ?
BICC Bearer Network
Modify Bearer
“Play it again Sam!”, and:
Intro
OOM
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
18
“Use of OOM and UML to define Signalling Requirements”
Supplementing BICC Signalling
Requirements
5/6
And there’d be much more to be modelled!
BNC
SCF
SLP-A
BIWF-Addr=(Y):BNC-ID=(1)
SLP-C
SLP-B
Termination(a)
(5)
End
Point A
(1)
CCA
CBC
O-CSM
A
(2)
T-CSM
C
CSF
BIWF Contr ol P or t
End
Point C
(2)
(2)
Context
Logical Port-A
Termina tion
A1
BNC
External
Logical Port-C
Termina tion
C1
Co nnectio n
Internal
Internal
Termination States
- Null
- Loop Back External Signal (loopback)
Internal
- Loop Back Internal Signal
Stream Mode
- Cut-Through Towards Context (Receive)
- Cut-Through From Context (Send)
- Cut-Through Both (Send / Receive)
BNC
Termination(c)
BIWF-Addr=(Y):BNC-ID=(2)
CCA
Bearer
S ign all in g
(opti onal )
(3)
BIWF-Addr=(Z):BNC-ID=(4)
Connection
(3 party)
Context(2)
Configuration 2
Termination(e)
Local Call Instance
(3)
Termination(g)
BNC
External
Termination
B1
Logical Port-B
BIWF
BNC
BIWF-Addr=(X):BNC-ID=(4)
(3)
OOM
BNC
Termination(f)
BIWF-Addr=(Y):BNC-ID=(3)
BNC
Connection
(Hold)
Connection
(2 party)
BNC
BIWF-Addr=(W):BNC-ID=(4)
Context(4)
BNC
External
Configuration 3
Context(3)
BIWF-Addr=(X):BNC-ID=(5)
Termination(h)
Local Call Instance
BIWF (X)
BICC
Results
(1)
BNC
Termination(d)
CCA
(5)
CCU C ontrol Port
(4)
Bearer
S ign all in g
(opti onal )
Intro
(1)
B
(4)
Local Call Instance
End
Point B
(5)
BNC
BIWF-Addr=(Y):BNC-ID=(4)
Context(1)
Configuration 1
Local Call InstanceT-CSM
Termination(b)
Connection
(2 party)
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
19
“Use of OOM and UML to define Signalling Requirements”
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
Intro
OOM
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
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
20
“Use of OOM and UML to define Signalling Requirements”
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?
Intro
OOM
 Learning curve steep enough?
BICC
 Return on investment?
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
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”
21
“Use of OOM and UML to define Signalling Requirements”
Personal Observations
“Contemporary” factors
“Hidden” factors
 Time pressure
 Conceptual work
-> get out standards fast
 Little resources available
-> reduce efforts to the minimum
 Increased Fluctuation
-> people change,
know-how changes...
 Current quality control system
Intro
OOM
-> iterative approach: changes to
standards as implementers
discover imperfect parts
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
– 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
22
“Use of OOM and UML to define Signalling Requirements”
Personal Long-term Views
Think positive!
Summing up
 Complexity in telecom will
continue to increase
 Need for conceptual work
-> a common understanding of
technical and conceptual
issues is indispensable
 Parties with particular interest
in transparency:
Intro
OOM
– Governments:
regulation, lawful interception
– Service Providers:
service convergence
challenge, cope with network
complexity
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
– 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
23
“Use of OOM and UML to define Signalling Requirements”
Thank you!
...and enjoy your stay in Switzerland
...despite the *?+!%ç&*/ weather!
coffee break
now?
psst!
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
24
“Use of OOM and UML to define Signalling Requirements”
Supplemental
BACKUP
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
25
“Use of OOM and UML to define Signalling Requirements”
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)
Intro
OOM
 “Enterprise Modelling with UML” by Chris Marshall (Addison-Wesley,
Object Technology series, 1999)
BICC
Results
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
26
“Use of OOM and UML to define Signalling Requirements”
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
ITU Workshop on "Use of Description Techniques"
Geneva, 23 November 2002
27