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From: donp@APOLLO.COM (Don Preuss)
Newsgroups: comp.protocols.iso
Subject: Re: X-WINDOWS & OSI
Message-ID: <8906201531.AA01491@xuucp.ch.apollo.com>
Date: 20 Jun 89 15:35:07 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 46


>    If you have an urgent need to run X over an OSI net, the mapping onto
>    transport is a sensible short term fix.  I do my work on TCP/IP and X.25(80)
>    nets.  With the possible exception of X.400, real OSI services are still a
>    good way down the road.  I see no reason to rush an X/OSI mapping.
>    
>    Steve
    
The reason this is coming now, and the reason for the urgency in making a decision
is that there is currently a proposal on running X over OSI in X3H3.6. Since it is
being considered in a standards body, this needs to be discussed. 

At the recent NIST OSI Workshop I held an ad hoc meeting of people interested in this
problem. There was a large attendence from members of the VT sig, plus a few other 
people knowledgeable and/or interested in this. The primary reason I held the meeting
was to get a sense of the workshop on where X should belong, and get some feedback on
the DEC proposal. 

The feeling is that although X will run more quickly and efficiently directly on transport,
and that there will be fewer duplication of services, it should really sit on top of
the OSI stack, and use ACSE and presentation. This will allow future use of 
presentation security, CCR and management features of OSI, in addition to authentication 
and whatever else might creep up.

The only place where a major (compared to transport) performance hit comes when running
over S+P is on OPEN DISPLAY. Instead of just doing a CR, we are using ACSE. However, once
the connection is established, we could use a generic-octect transfer syntax, and for a
very small cost in perfomance, run over presentation.


]	    I have some reservations on this approach [running on S+P] , though. In my opinion, it is
]	somewhat too ``minimalist'', and a real ``OSI X-Window'' should include
]	a proper definition of the X protocol in the ASN-1 language; however, I
]	realize that the time to develop + demonstrate such a tool could be a
]	bit long, and that its advantages have to be weighted against achieving
]	an ANSI (then ISO) standard in a short time frame.
]
]	Christian Huitema

I agree completely. 

donp

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