Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!oliveb!orc!decwrl!chico.pa.dec.com!klee From: klee@chico.pa.dec.com (Ken Lee) Newsgroups: comp.protocols.iso Subject: Re: X/Windows and OSI Message-ID: <2440@bacchus.dec.com> Date: 11 Jan 90 22:30:47 GMT References: <1990Jan11.115009.27548@gdt.bath.ac.uk> Sender: news@decwrl.dec.com Reply-To: klee@decwrl.dec.com Organization: DEC Western Software Laboratory Lines: 130 In case you missed it, here is the original MAP/TOP statement. MAP/TOP is a U.S. consortium of industrial computer users, including General Motors, Boeing, etc. They are one of the largest groups of OSI users in the U.S. and are very influential with U.S. and computer networking international standards. ANSI, the U.S. standards organization, is standardizing the X Window System protocol. Part of this work may include an OSI protocol mapping. There is currently a debate (including theoretical work and prototyping) within ANSI as to whether this mapping should be at the ACSE level or Transport level. Detailed protocol mapping for each have been submitted. If you have comments on this issue, please contact me this week. The ANSI window systems committee will be meeting next week (Jan. 12-16) to try to resolve this issue. Ken Lee Secretary, ANSI X3H3.6 (Computer Graphics - Window Systems) klee@decwrl.dec.com ============================================================== Manufacturing Automation Protocol & Technical and Office Protocol Users Group 89-00-002-ARC December 13, 1989 MAP/TOP LIAISON TO ANSI X3H3.6 A high priority requirement of the MAP/TOP Users Group is to use X-Window over OSI networks. As the MAP/TOP Users Group is committed to use interna- tional or national standards whenever possible, it welcomes the work X3H3 is doing to standardize the X-Data Stream. However, the MAP/TOP Users Group not only needs a Data Stream standard, but also needs a standardized mapping of the X-Data Stream Definition onto OSI. Without a standardized mapping, there is no way of ensuring interoperabil- ity of implementations of the X-Data Stream from different vendors over OSI networks. To promote the timely adoption of such a mapping, the MAP/TOP Users Group sent X3H3 a position statement in September 1989 (see 89-00-0002 USG) encouraging X3H3 to include in the X-Data Stream standard a mapping at the ACSE/Presentation level of OSI. As X3H3 has not yet made a decision on the type of mapping to incorporate in the X-Data Stream definition, the MAP/TOP Users Group wishes to reiterate its position that the mapping should be on the ACSE/Presentation level of OSI. We hope the following will help X3H3 understand the reasons behind this position: 1. OSI Naming and Addressing (See ISO 7498-2) comprises all seven layers. Addressing at the ACSE level will enable an X-Client to address an X- Server in a standard manner, but some ad hoc addressing mechanism would have to be invented to handle client addressing at a lower level. 2. OSI Security is provide by functions in the Application Layer of OSI. Thus, OSI access control facility will not be available below the Application Layer. 3. OSI Directory services is an Application Layer function. It is highly desirable that X-Applications be able to locate X-Servers through a standard use of X-500 Directories. 4. In the event of loss of communication, re-establishment to a particu- lar instance of a process is available only in OSI if ACSE is employed. 5. If a Client application or a Server using the X-Data Stream Definition is also going to use other OSI protocols (e.g., VT for process selec- tion or FTAM for down loading fonts), implementation consistency (sin- gle OSI interface) will be achieved only if these protocols operate at - 2 - the same level of OSI (i.e., ACSE). 6. Mapping to the ACSE/Presentation level of OSI is architecturally (for OSI) correct. We believe that if X-Data Stream is not mapped to use OSI at this level, there may be some negative reaction from the OSI committees in ISO and ISO National Bodies. This could hinder the fast-track process for the X-Data Stream Definition standard. As our goal is to get an international X-Data Stream Definition as quickly as possible, we strongly advise against doing anything which could jeop- ardize the rapid progression of your standard in ISO. X-Data Stream on OSI Prototyping In discussing the X-Data Stream Definition/OSI mapping at the Technical Forum meeting of December 11, 1989, it was reported that X3H3 is awaiting the results of prototyping work to help make the decision as to which map- ping to choose. We see prototyping as a valuable tool to determine if a mapping candidate is correct. It is far better to ensure accuracy before the standard goes to Public Review. However, a few implementors at our meeting cautioned against attaching too much weight on these results with regard to efficiency. As these implemen- tations are just prototypes and not finished products, they will probably not receive the attention and tuning for efficiency a finished product would receive. Therefore, we feel performance figures from these proto- types probably are not indicative of the performance levels which can be expected of X-Window products based on the X-Data Stream Definition. For example, a prototype may utilize the user interface to gain access to OSI services, whereas an X-Product may bypass such an interface and use a fas- ter internal OSI service interface. CONCLUSION In view of the above, the MAP/TOP Users Group urges X3H3 to adopt an ACSE/Presentation mapping and to progress this mapping with the X-Data Stream Definition as quickly as possible. Ken Lee DEC Western Software Laboratory, Palo Alto, Calif. Internet: klee@decwrl.dec.com uucp: uunet!decwrl!klee