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URN Focus Group

Background on URN Question
Purpose of URN Focus Group
SG 17 Action plan

Background on URN Question

At its meeting in November 1999, Study Group 10 approved Question 12/10: URN: User Requirements Notation to study what new Recommendations and other documents are required in order to define a notation, methods or revised notations for capturing and analyzing user requirements. Subsequently, Q.12/10 was approved by WTSA-2000 at its meeting in Montreal, in September-October 2000. Within the new Study Group 17, this Question for study became Q.18/17.

The URN is defined to have the following capabilities:

a) describe scenarios as first class entities without requiring reference to system sub-components, specific inter-component communication facilities, or sub-component states;

b) capture user requirements when very little design detail is available;

c) facilitate the transition from a requirements specification to a high level design involving the consideration of alternative architectures and the discovery of further requirements that must be vetted by the stakeholders;

d) have dynamic refinement capability with the ability to allocate scenario responsibilities to architectural components;

e) be applicable to the design of policy-driven negotiation protocols involving dynamic entities;

f) facilitate detection and avoidance of undesirable interactions between features;

g) provide insight at the requirements level that enables designers to reason about feature interactions and performance trade-offs early in the design process.

h) provide facilities to express, analyse and deal with goals and non-functional requirements;

i) provide facilities to express the relationship between goals and system requirements;

j) provide facilities to capture reusable analysis and design knowledge related to know-how for addressing non-functional requirements;

k) provide facilities to trace and transform requirements to other languages (especially ITU-T notations and UML);

l) provide facilities to connect URN elements to external requirements objects;

m) provide facilities to manage evolving requirements.

Recommendation Z.150, which provides language requirements and a framework for URN, was approved in February 2003. Description of the languages and of methodological aspects are intended to be submitted for consent by end of 2003.

Purpose of URN Focus Group

The URN Focus Group was mandated to progress the work on the draft Z.URN Recommendations between ITU-T SG 17 meetings. It collects requirements, suggestions, and informal contributions related to Q.18/17 and then integrates them. In effect, the URN Focus Group leads most of the technical development behind URN, according to the Q.18/17 work programme.

The URN Focus Group has produced and presented several versions of documents that refine the URN objectives and define the two complementary languages proposed so far: the Goal-oriented Requirements Language (GRL) and the Use Case Map notation (UCM). The most recent versions are available as delayed contributions (Canada) at the February-March SG 17 meeting:

  • D 15: Draft Recommendation Z.151 - GRL: Goal-oriented Requirements Language
  • D 16: Draft Recommendation Z.152 - UCM: Use Case Map notation

Two additional documents linking URN to other notations (Z.153 - URN: Methodological Approach) and to UML 2.0 (Z.159) are also planned.


At the moment, the URN Focus Group is composed of about 35 practitioners and researchers but it is expanding and is open to all interested contributors.

Additionally, the Focus Group receives indirect input from several other user communities (UCM User Group, ~200 members), and international research communities (goal-oriented and agent modelling, feature interaction, formal description techniques, and performance).

Please contact the Q.18/17 Rapporteur if you are interested in collaborating/contributing. Your ideas, comments, suggestions, and expertise are much needed and would be most appreciated.


Most of the discussions and work in the URN Focus Group is done electronically, by e-mail. A public Website ( also contains draft Recommendations and presentation material. Development of prototype tool support, which help validate and experiment with the various concepts and notations developed in GRL and UCM, has also progressed. These tools are used in various research projects initiated by industrial and academic collaborators.

- Use Case Map Navigator:

- OME3 (for GRL):

Please contact Daniel Amyot ( to join the URN Focus Group.

SG 17 Action plan

At its meeting in November 2002, Study Group 17 approved the continued operation of the URN focus group until the next Study Group 17 meeting currently scheduled to begin on September 10, 2003.

The objectives are those identified in the Q.18/17 action plan, namely:

  • Develop metamodels for GRL (Z.151) and UCM (Z.152)
  • Finalise concrete graphical grammars and interchange formats for GRL and UCM
  • Finalise definitions of propagation rules in GRL models
  • Provide a working draft document for Z.153, with a particular emphasis on the relationships between GRL and UCM, and on the conversion from UCMs to MSCs. Issues for connecting URN to UML, ASN.1, TTCN, SDL, and eODL will be collected as well.
  • Initiate work towards a UML profile for URN (Z.159)
  • Support and promote the use of the GRL and UCM languages with prototype tools, tutorials, and marketing/technical documentation.


  • September 2003: Z.151 (GRL) consent sought (might be postponed)
  • September 2003: Z.152 (UCM) consent sought (might be postponed)
  • September 2003: Z.153 (Methodological Approach) first draft
  • March 2004: Z.153 (Methodological Approach) consent sought (delayed from Sept. 2003)
  • March 2004: Z.159 (UML profile for URN) consent sought


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