@make[report]
@section[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 the autumn
of this year.  An important feature in the transition is keeping in step
with the ISO transition in the rest of Europe.
@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 or 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.
@section[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 this set in the community.
@section[FTP]
FTP will be replaced by ISO File Transfer and Minipulation.  The standard for
this is well advanced and serious investigation of the protocol is under way
both in the community and by manufacturers.
@section[Job Transfer]
The ISO protocal JTM is currently being studied.  One 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, so a relay that converts between old and new
should be capable of performing well.  With FTP, we will probably need to
rely on the ???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 new protocol hosts.

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 both resources will be needed for
the transition and an education of our users will be needed to convince them
of the need for transition.


@flushright[B. A. C. Gilmore]