Question 26/VII - Open Systems Interconnection (OSI) presentation and
session layers (continuation of part of Question 42/VII studied in
19851988 on OSI presentation and session layers)

Considering

(a) that Recommendation X.200 specifies the reference model of Open
Systems Interconnection for CCITT applications;

(b) that Recommendation X.210 specifies the layer service definition
conventions of Open Systems Interconnection for CCITT applications;

(c) that Recommendation X.220 specifies the use of X.200-Series
protocols in CCITT applications;

(d) that Recommendations X.215 and X.225 specify the session service and
protocol of Open Systems Interconnection for CCITT applications;

(e) that Recommendations X.216 and X.226 specify the presentation
service and protocol of Open Systems Interconnection for CCITT
applications;

(f) that administrations and users in many countries are applying the
Open System Interconnection family of Recommendations to public networks
now existing or due to be available in the near future;

(g) that close collaboration and liaison with other international bodies
(e.g., ISO, IEC) studying Open Systems Interconnection is highly
desirable,

therefore, work should continue to determine:

1. Presentation layer

What further refinements are required for the presentation layer
services and protocol, Recommendations X.216 and X.226, to provide
additional capabilities, such as data encryption and compression? What
additional work is required to provide formal descriptions of the
presentation services and protocol? What is required to validate
presentation layer protocol specifications to avoid potential errors?
What is required to provide for registration of transfer syntaxes?

2. Session layer

What further refinements are required for the session layer services and
protocol, Recommendations X.215 and X.225, to provide additional
capabilities, such as symmetric synchronization? What additional work is
required to provide formal descriptions of the session services and
protocol? What is required to validate session layer protocol
specifications to avoid potential errors?

3. Liaison

What is necessary to maintain cooperation with other international
organizations (e.g., ISO/IEC JTC 1) in activities concerning the
presentation and session layers for OSI?