@make[report]
@heading[ISO Transition Plans (some brief comments)]
The ISO Transition Plans still correspond well with the outline given by
Peter Linington at Networkshop 1984.  However, since then the ISO Transition
Committee has been meeting and a major report will be available in 
@b[the autumn] of this year. 

 An important feature in the transition is keeping in step
with the ISO transition in the rest of Europe
to ensure that we can apply the maximum pressure on @b[manufacturers] to produce
the necessary protocols.
@section[Current Position]
The transition will be handled in two distinct parts.
@begin[enumerate]
At the network Level (and below)

Upper levels
@end[enumerate]
@section[Network Level]
The intention is to switch from the current position of Yellow Book running over
X.25 (1980) to one of running just X.25 (1984) as the network layer (see fig 1).
This change is dependant on the timing of our PSE supplier, GEC, supplying the
relevant software.  GEC is unlikely to do this in advance of BT for PSS, who
may start providing the necessary facilities of X.25 (1984) later next year.
We will not be able to change the entire Academic Community in one go, so there
will be a requirement for a considerable number (and type) of Gateways to handle
the necessary conversions.

Hopefully, the user can be protected from this transition, although addressing
changes will have a major impact, particularly where the user is currently
expected to have to know and use addresses rather than names.
@section[Upper Levels]
The upper level transition can be handled in application by application stages
as the various ISO (or CCITT) protocols become available.
@subsection[Mail]
The CCITT protocol X.400 is being accepted as the international standard.
Some implementations have already been produced although they will need to be
changed as the standard matures, in particular, the exact subset of level 4-6
to be used may change.  X.400 will be the first of the standard
application protocols to appear  in the community.
@subsection[FTP]
FTP will be replaced by ISO File Transfer and Manipulation.  The standard for
this is well advanced and serious investigation of the protocol is under way
both in the community and by manufacturers.
@subsection[Job Transfer]
The ISO protocal JTM is currently being studied.

@section[Summary]
  One continuing problem with these protocols
is that there is still no agreement on the particular aspects of the levels
4-6 is to be used, in particular at present X.400 and FTAM use different subsets
of the session level.

The communities very success with the coloured book protocols mean that we do
have a significant transition problem.  Mail is probably the easiest as mail
relays are already in constant use.
New relays that are capable of converting between Gray Book and X.400 shall
cushion the user from the effects of a dual standard community and even some
benefits may be expected as manufacturers, such as DEC on VMS, properly
integrate 'standard' mail into their own mail systems.  FTP is more of a
problem, although the quantity of traffic appears to be a lot less,
we will probably need to
rely on the major hosts supporting both protocols for a period, although 
on-the-fly gateways are being investigated.

From the user point of view, some features may disappear during the transion
period, others may only be available between  hosts both running the
 new protocols.

We cannot stay on the old protocols, as new machines arrive in the community
the manufacturer will not be willing to keep implementing 'coloured book'
protocols.

The work is really only just beginning and resources will be needed both for
the transition and an education of our users will be needed to convince them
of the need for the transition.


@flushright[B. A. C. Gilmore
19 June '85]