Question 23/VII - Open Systems Interconnection (OSI) architecture
(continuation of part of Question 42/VII studied in 19851988 on OSI
architecture)

considering

(a) that administrations in many countries are planning to establish
telecommunications services which exploit the networks now existing or
due to be available in the near future;

(b) that these services may be carried on different types of networks;

(c) that users of these services need to communicate with each other
irrespective of the diversity of interconnected networks;

(d) that methodical representation of network services will further
promote the effective and efficient use of networks;

(e) that accommodation of conflicting services requirements and network
constraints can be affected through the analysis of service and network
functions. This analysis should lead to a universally applicable logical
structure which may be used in the development of compatible service,
interface and procedure definitions;

(f) that this structure should as far as possible accommodate existing
Recommendations to allow the steady evolution of networks providing the
new services;

(g) that the development of new telecommunications services necessitates
in some cases the study of higher layer service definitions and protocol
specifications;

(h) that close collaboration and liaison with other Study Groups and
other international bodies studying reference models and functional
profiles (e.g., ISO, IEC) is highly desirable to ensure the widest
applicability of resulting Recommendations,

therefore, work should continue to determine:

1. Reference model

What further refinements are required for Recommendation X.200?

In particular, studies should include:

a) reference model architecture, including impact of OSI management,
transaction processing and distributed processing;

b) harmonize the reference model and ISDN architecture;

c) naming and addressing requirements, including which OSI entities
require naming or addressing, the structure, if any, of such names and
addresses and the administrative requirements for management of OSI
names and addresses, including registration authority requirements,
where appropriate;

d) security;

e) connectionless mode;

f) procedure for answering questions relative to the reference model.

2. Service conventions

What further study is required to refine Recommendation X.210 to
elaborate the detailed properties of service primitives, including
service oriented interactions among application service elements within
the application layer?

3. Use of X.200-Series protocols

What further study is required to maintain Recommendation X.220, so that
it will accurately portray usages of X.200-Series protocols in CCITT
applications? Studies should include profiles and classification
schemes, with particular attention to the work of ISO/IEC JTC 1 on
functional standardization.

4. Liaison

What is necessary to maintain cooperation with other international
organizations (e.g., ISO/IEC JTC 1) in activities concerning reference
models of Open Systems Interconnection and functional profiles?