🚀 go-pugleaf

sch@sequent.com (Steve Hemminger) writes:

>* User friendly.  Exchanging X.400 mail addresses is not friendly.
>  Having to have full information about every other machine you want to
>  talk to is not friendly (i.e Network, Transport, Session, Application
>  ...)

This is solved by OSI with the X.500 directory services in a very elegant
way. Unfortunately, most people don't know about it and still worry
about ugly mail adresses. With the information provided in my
 .signature, you should be able to enter something like

M Kuhn, Uni Erlangen, DE or
Markus Kuhn, Computer Science, Universitaet Erlangen-Nuernberg, Germany

or something else and after a few seconds your mailer should know
everything about my mailer (e.g. address, document types allowed, ...).
E.g. test the de DUA that comes with ISODE.

Markus

---
Markus Kuhn, Computer Science student -=-=- University of Erlangen, Germany
Internet: mskuhn@immd4.informatik.uni-erlangen.de  |  X.500 entry available
-A distributed system is one in which the failure of a computer you didn't-
-even know existed can render your own computer unusable. (Leslie Lamport)-

mskuhn@cip.informatik.uni-erlangen.de (Markus Kuhn) writes:


>M Kuhn, Uni Erlangen, DE or
>Markus Kuhn, Computer Science, Universitaet Erlangen-Nuernberg, Germany

>or something else and after a few seconds your mailer should know
>everything about my mailer (e.g. address, document types allowed, ...).
>E.g. test the de DUA that comes with ISODE.

Define a few seconds. I guarantee that you will find non-obscure, non-rare
cases which will take well over 30 sec to complete. At current rates of
growth, coverage will be under 20% of the Internet-at-large for some time
to come. 

It works well for self-managed domains, self-consistent arenas like .de
which is a heavily structure/managed network. It works poorly in the
anarchy of the Internet.

lightweight protocols/services win hands down. The community would have
been better served by a targeted service for mail location/delivery and
not a catch-all. 

-George
--
                         George Michaelson
G.Michaelson@cc.uq.oz.au The Prentice Centre      | There's no  market for
                         University of Queensland | hippos in Philadelphia
Phone: +61 7 365 4079    QLD Australia 4072       |          -Bertold Brecht

In article <BtMtov.9xK@immd4.informatik.uni-erlangen.de> mskuhn@cip.informatik.uni-erlangen.de (Markus Kuhn) writes:
> sch@sequent.com (Steve Hemminger) writes:
> >* User friendly.  Exchanging X.400 mail addresses is not friendly.
> >  Having to have full information about every other machine you want to
> >  talk to is not friendly (i.e Network, Transport, Session, Application
> >  ...)

> This is solved by OSI with the X.500 directory services in a very elegant
> way.

Only if you have cheap real-time access to the database. X.400 and X.500 is
a solution for rich folks or service bureaus. It doesn't scale well to low
bandwidth loosely-coupled systems.

As X.400 gets more common, I'm getting more and more bounces. Worse, I'm
getting bounces from replies to messages originated in X.400 land, where
the gateway didn't put an unambiguous address in the sender field. Because
there is no such thing as an unambiguous address in X.400.

> -A distributed system is one in which the failure of a computer you didn't-
> -even know existed can render your own computer unusable. (Leslie Lamport)-

Well, that's why a loosely coupled system is useful, and the basic problem
with X.500.
-- 
Peter da Silva                                               `-_-'
$ EDIT/TECO LOVE                                              'U` 
%TECO-W-OLDJOKE Not war?                        Have you hugged your wolf today?
Ferranti Intl. Ctls. Corp.      Sugar Land, TX  77487-5012       +1 713 274 5180

In article <ggm.714969881@brolga> ggm@brolga.cc.uq.oz.au (George Michaelson) writes:
>lightweight protocols/services win hands down [over X.500]. The community
>would have been better served by a targeted service for mail
>location/delivery and not a catch-all. 

The community has a lightweight protocol which can be used for mail location
and delivery. It is called DNS. The tree structure used in DNS is almost
identical to that used in X.500, as are the procedures for navigation,
replication and distribution.

The major differences between X.500 and DNS are i) the provision of the
'attribute' data model in X.500 and ii) the more powerful operations
(such as modify) in X.500.

That DNS is not widely used for mail location/delivery(*) suggests
that there was actually a need for some of the complications in X.500.

Andrew Waugh

(*) for users. DNS is, of course, used extensively to look up IP addresses :-).

ggm@brolga.cc.uq.oz.au (George Michaelson) writes:

>Define a few seconds. I guarantee that you will find non-obscure, non-rare
>cases which will take well over 30 sec to complete. 

I agree with you that the PARADISE pilot X.500 network is quite slow on
some links. The cause for this is mainly a lack of replication. Today,
relication is used in PARADISE only for the first two levels (root and
countries), because the implementation used in this pilot (ISODE QUIPU 8.0)
uses only a very simple replication method, i.e. it copies complete EDB
files, so deeper shadowing would cause a lot of waste of bandwidth.

The next release of the X.500 standard (92) defines a much more sophisticated
replication scheme, where only the changes in the data base are distributed
and where both delivery and polling are possible. With these extensions,
I believe that it will be quite common, that there are a few big DSAs in
each country that replicate nearly the complete database (perhaps without
large JPEG photos and security sensitive attributes). Then accesses should
be possible in less then 3 seconds for nearly all entries and in less
then a second for the more often used entries that are even replicated in
the local DSA. With these developments in mind, you might see the world
wide X.500 DSA net more like a kind of news system that forwards changes
then the 'ask the next DSA' system that it is today.

So please keep in mind that PARADISE is just a prototype pilot and don't
kill the child before it even is born.

BTW: it is not very difficult to write a mail UA that makes life easy
in a slow X.500 system. At first you have to enter the name of the
person to which you'd like to send a message. A name resolving process
is forked while you are in the editor writing the mail. If the name has
been resolved, you are presented the result, e.g.

     Markus Kuhn, Studenten, Informatik, Universitaet Erlangen-Nuernberg, DE

after leaving the editor that you got from entering

     M Kuhn, Uni Erlangen, DE

or only 'M Kuhn' if you are sitting in the same organisation. A cache in the UA
makes things even more comfortably (e.g. have you ever tried CDCs osilookup?).

>It works well for self-managed domains, self-consistent arenas like .de
>which is a heavily structure/managed network. It works poorly in the
>anarchy of the Internet.

If X.500 will be the reason why people are forced to give the Internet
a little bit more structure/management, then this can only be a benefit. :-)

What I enjoy with X.500 is it's enourmous flexibility. It's large advantage
is that it is definitely not a simple-minded special purpose protocol
only designed for finding mail recipients. It's well designed information
structure makes it also useful for many other tasks (e.g. managing
group communication systems, maintaining lists of ftp sites, give
you valuable additional information about DNS, ...)

X.500 is much simpler than 10 lightwight special purpose protocols,
and you get an excelent worldwide name space for many applications.

Markus

---
Markus Kuhn, Computer Science student -=-=- University of Erlangen, Germany
Internet: mskuhn@immd4.informatik.uni-erlangen.de  |  X.500 entry available
-A distributed system is one in which the failure of a computer you didn't-
-even know existed can render your own computer unusable. (Leslie Lamport)-

peter@ferranti.com (peter da silva) writes:

>Only if you have cheap real-time access to the database. X.400 and X.500 is
>a solution for rich folks or service bureaus. It doesn't scale well to low
>bandwidth loosely-coupled systems.

I am especially interested in using X.400/X.500 over periodic dialup
connections with slow lines (e.g. 9600bits/sec). If you can't bring the
user to the database in realtime, then bring the database to the local system.
If I see the huge traffic that is transported in the USENET every day from
node to node in dialup systems, then it should be no problem to have a
permanent copy of large portions of the directory information tree using
the X.500(92) DISP (directory information shadowing protocol).

It is not clearly specified in the standards, but I believe it is all right
if you set up a network that consists of DSAs that only support the DISP
instead of the usual DSP. Only a few DSAs in the net have to support 
also DSP, so that the rest of the world can ready their shadows.

Comments?

I am interested in implementing such a biest. The DISP protocol is really
simple compared to DSP. I agree that X.400 is not much fun without a
directory, but believe me, the X.400/X.500 combination (together with
the X.gc stuff for NEWS) will be the prefered email system in a few years!

Markus

---
Markus Kuhn, Computer Science student -=-=- University of Erlangen, Germany
Internet: mskuhn@immd4.informatik.uni-erlangen.de  |  X.500 entry available
-A distributed system is one in which the failure of a computer you didn't-
-even know existed can render your own computer unusable. (Leslie Lamport)-

In article <id.ZIRS.GD@ferranti.com>, peter@ferranti.com (peter da silva) writes:
|> As X.400 gets more common, I'm getting more and more bounces. Worse, I'm
|> getting bounces from replies to messages originated in X.400 land, where
|> the gateway didn't put an unambiguous address in the sender field. Because
|> there is no such thing as an unambiguous address in X.400.
|> 
 
Sorry, I do not understand these sentences, the information in them seem to be
very strange to me.

1) Why should the gateway put an address in the sender field?
2) What do you mean with unambiguous address?
3) Why do you think that X.400 does not know such thing like an unambiguous 
   address?
4) What are you doing with an address of the sender field in a reply?

-- 

Michael Storz
================================================================================
                                      !   X.400 : G=michael;S=storz;OU1=lrz;
   Leibniz-Rechenzentrum              !           P=lrz-muenchen;A=dbp;C=de
   Barer Str. 21                      !   RFC822: storz@lrz.lrz-muenchen.dbp.de
   8000 Muenchen 2                    !   Fax   : ++ 49 89 2809460
   Germany                            !   Tel   : ++ 49 89 2105 7420
================================================================================

In article <BtMtov.9xK@immd4.informatik.uni-erlangen.de> mskuhn@cip.informatik.uni-erlangen.de (Markus Kuhn) writes:
>This is solved by OSI with the X.500 directory services in a very elegant
>way. Unfortunately, most people don't know about it and still worry
>about ugly mail adresses.
Oh. I haven't seen any actual X.500 implementation, but: 

-How will I get access to names of users at other sites

-Will I do interactive lookups over public X.25 in perhaps 2400bps ?

-Will my PTT, which thinks it owns x.400 allow me to talk to ANYBODY at all.

-How do I do store&forward mail, still using x.500 ?

Anybody have a clue ?

/Per
-- 
-----------------------------------------------------------------------------
Per Andersson - ppan@nobeltech.se (perand@stacken.kth.se on free time)
Managing networks at, but not speaking for Nobeltech AB, J{rf{lla, Sweden
-----------------------------------------------------------------------------

ppan@nobeltech.se (Per Andersson) writes:
>Oh. I haven't seen any actual X.500 implementation, but: 

I believe that 98% of the people that use X.500 today on the Internet
use the Paradise implementation that comes with ISODE 8.0. It has
a DSA and several different interactive user agents. It's quite fine,
but I feel that it's still a research version not 100% suitable for
everyday usage. E.g. installation is a little bit more complicated
then with other popular programs (e.g. elm, GNU things).

>-How will I get access to names of users at other sites

For the user, there are at least 2 different kinds of access to the
directory database that I've seen implemented:

a) browsing

   The X.500 directory is organized like a tree. The whole world is
   represented by the root, the children of the root are all
   countries and international organizations and below the country
   nodes you have organizations (e.g. my university). These
   organizations are perhaps further subdivided in departments
   (organizational units) like "Computer Science" etc.
   The whole structure looks like a file system with directories
   and files and you can browse in it as you can do this in
   a file system (with commands, with a nice GUI, ...)
   Each entry has attributes associated with it. E.g. my entry
   has attributes that describe my phone number, my address (email
   and postal), my favourite drink and even my face (with a small
   JPEG encoded photo). An access control system allows you to
   restrict some users (e.g. from outside your company) to read
   only selected attributes.

b) searching

   Some of the more intelligent user agents ask you a few questions
   or ask you for a guess where in the tree the person you search might
   be located (you know perhaps the country and a part of the name
   of the organization). Then these programms will perform a search in 
   the database and try to find what you searched for (e.g. a person,
   a department, a printer, a fileserver, a contact person, a document, ...)
   The attributes of the entries found will be displayed to you.

All these accesses to the database are done over a protocol called DAP
(directory access protocol). Two kind of programs are involved: The
DUA (directory user agent) implements the user interface and sends the
querry commands via DAP to the DSA (directory service agent, the server)
which contains a part of the database and querries other DSAs using the
DSP (directory system protocol).

(DUA,DSA,DAP,DSP, all right? ;-)

>-Will I do interactive lookups over public X.25 in perhaps 2400bps ?

Thats possible, of course. There are several public DUAs available on
the Internet and via different X.25 networks (e.g. the German WIN).
Over very slow lines, it might be more comfortable to have a local
DUA and using the directory access protocol over the X.500 line.

>-How do I do store&forward mail, still using x.500 ?

Today, if you want to use X.500, you need access to a DSA
in order to resolve querries, and this DSA must have permanent
contact with other DSAs, so that eventually (with several intermediate
DSAs perhaps) you are in contact with every DSA on this world.
This is no problem if you are permanently connected to a large network
with lots of DSAs that are again connected to other DSAs on other
nets (e.g. Internet, many X.25 nets and big LANs). In a dialup
environment (where you need a store and forward system for mail),
things become a little bit more difficult. The database must have
copies of many entries on a lot of different DSAs, because the DSAs
are not connected all the time. In extreme cases, it might be necessary
to have huge copies of the whole tree in each dialup DSA and differential
updates of the copies will be propagated through the network in a store
and forward manner using DISP (directory information shadowing protocol,
the final X.500 abreviation for today :-). DISP is still a draft standard
today and consequently hasn't been implemented widely.

The X.500 directory system may be useful for both finding persons
on the net and doing routing decisions.

I hope this was an answer to your question (correct me if not!).

Markus

(in the tree: Markus Kuhn, Studenten, Informatik, Uni-Erlangen,
Germany. You should be able to find this entry easily with the 
information in my .signature below using a good DUA.)

-- 
Markus Kuhn, Computer Science student -=-=- University of Erlangen, Germany
Internet: mskuhn@immd4.informatik.uni-erlangen.de  |  X.500 entry available
-A distributed system is one in which the failure of a computer you didn't-
-even know existed can render your own computer unusable. (Leslie Lamport)-
QUIT
omputer you didn't-
-even know existed can render your own computer unusable. (Leslie Lamport)-