Question 3/VII - Technical characteristics of connectionless services in public networks (continuation of Question 4/VII studied in 1985-88) considering (a) that Recommendation X.327 defines the general arrangements for interworking between Packet Switched Public Data Networks (PSPDNs) and private data networks for the provision of data transmission services; (b) that ISO has developed OSI Connectionless Network Service; (c) that certain applications (e.g. point-of-sale, telemetry) do not utilize some typical features of connection-orientated services such as network provided sequence control, error recovery, or protection against loss or duplication of data; (d) that certain applications may need network-provided multicast services; (e) that there exists a "fast select" facility in Recommendation X.25 which is an essential facility; (f) that there may exist a need for internationally standardizing the network services to support applications of the types defined above; (g) that Study Group I is responsible for the definition and operational aspects of data transmission services, What additions to existing Recommendations or new Recommendations are required to specify the service(s) and interface(s) related to the above considerations? Question 4/VII - Network performance and Quality of Service in Data Communications Networks (continuation of Question 29/VII, studied in 1985-88) considering - that administrations and users each have an interest in ensuring that a good "Quality of Service" is provided on data communications networks; - that good "Quality of Service" is, in part, a consequence of good "network performance" in data communications networks; - that standard definitions for performance parameters are necessary for consistent evaluation of network performance; - that performance objectives and limits are necessary to ensure good network performance; - that for evaluating network performance, it is useful to define the conditions under which such objectives and limits should be measured; - that for comparing the network performance of several networks, it is useful to describe the conditions under which the performance descriptions apply; - that users' perceptions of network performance depend on how they interface with a service; - that users' needs for network performance depend on their applications; - that Recommendation X.140 defines general quality of service parameters; - that Recommendations X.130 and X.131 define network performance parameters and objectives for Circuit Switched Public Data Networks (CSPDNs); - that Recommendations X.134, X.135, X.136 and X.137 define network performance parameters and limits for Packet Switched Public Data Networks (PSPDNs); - that Study Group II is involved in the study of broad aspects of Quality of Service; the following topics should be studied: 1. Performance measurement How should the data communications network performance parameters in Recommendations X.130, X.131, X.135, X.136 and X.137 be measured? To assure consistency and compatibility of results: -how should statistically sound measurement programmes be designed? -what are the factors that influence the measured values (e.g., what is the meaning of the "busy hour" for data communications networks)? -what information should be included when reporting network performance? 2. Objectives and limits What objectives and limits should be assigned to the data communications network performance parameters in Recommendations X.130, X.131, X.135, X.136 and X.137? To assure a good network performance and Quality of Service: -to supplement the worst-case limits and to provide further guidance to network providers and users, what objectives should be established in Recommendations X.135, X.136 and X.137? -with regard to improvements in technology, how should the objectives and limits in Recommendations X.130, X.131, X.135, X.136 and X.137 be adjusted for the 1992-1996 time period? -what are the different Quality of Service needs for different data communications applications and what are the levels of network performance that support those needs? 3. Parameter relationships In order that users understand the relationships among the performance of their communications services, what are the relationships: -between the X.140 quality of service parameters for data networks and other general quality of service parameters and performance description frameworks for communications networks? -between the X.140 quality of service parameters and the PSPDN and CSPDN parameters defined in Recommendations X.130, X.131, X.135, X.136 and X.137? -between the X.140 quality of service parameters and the network performance parameters developed for ISDN, X.28 and X.32? -between throughput class as described in other Recommendations (e.g., X.25, X.75, etc.) and throughput parameters as defined in Recommendation X.135? What network performance parameters, objectives and limits should be recommended for the following interworking arrangements: -PSPDN/ISDN, - CSPDN/ISDN, - X.28 access to PSDNs, - X.32 access to PSPDNs? 4. Performance with Open Systems Interconnection (OSI) Systems -What is the quality of layer 1 bearer services required to ensure satisfactory PSPDN performance? -What is the relationship between signalled quality of service parameters and actual performance received? -What relationships exist between OSI layer service performance parameters and network performance? -How can the performance parameters defined in the various OSI layer service definition standards be interrelated? 5. How should the CSPDN performance parameters be clarified? -What are the allocation boundaries and what are the specific reference events that should be used in defining and allocating CSPDN performance? -What network performance parameters should be recommended for CSPDNs for the following areas? i) speed of service; ii) accuracy and dependability; iii) service availability; -What objectives and limits should be assigned to the CSPDN performance parameters and how do these values depend on different data communications applications? 6. Coordination with other Study Groups 6.1 The network performance models and parameters identified for data communications networks bear a close relationship with many of the models and network performance parameters appropriate for ISDNs. The studies of network performance in data communications networks should therefore be carefully coordinated with the studies in ISDN (Study Group XVIII). 6.2 The network performance models and parameters identified for PSPDNs are generally applicable to advanced packet technologies such as fast packet switching, frame relaying, and broadband ISDN. Close liaison should be maintained with those responsible for standardizing the advanced packet technologies (Study Group XVIII). 6.3 The quality of service parameters defined for data networks in X.140 are closely related to the general quality of service parameters being developed in Study Group II. Close liaison with that work should be maintained. 6.4 Close liaison should be maintained with those responsible for standardizing data communications network monitoring and maintenance (Study Group IV). Question 5/VII - Testing and verification of data communication protocols (continuation of Question 47/VII studied in 1985-88) considering (a) that Recommendation X.290 defines the general framework and methodology for the testing and verification of implementations of the X- and T-Series of the OSI protocol Recommendations; (b) that there is a need to develop standardized test suites for protocol Recommendations as a means to increase the probability of interworking; (c) that the area of ISDN is of greater importance for administrations; (d) that there is a need to continue collaborative work with ISO on conformance testing, and maintain alignment with ISO, if necessary, by appropriate means; (e) that the rules for cooperation between lower and upper testers during testing will be necessary, 1. What steps should be taken to achieve the standardization of test suites for OSI protocol Recommendations and the alignment of the conformance sections of these Recommendations with the methodology? 2. Which means are the most appropriate to manage and maintain in an efficient way CCITT manuals containing conformance test suites, given the specifics of these documents? 3. What is the need for testing and the applicability of Recommendation X.290 in the area of ISDN? (To be studied in liaison with Study Group XVIII.) 4. Which Test Management Protocol should be specified?