🚀 go-pugleaf

In article <391@lvbull.UUCP> sylvain@lvbull.UUCP (Sylvain Langlois) writes:
> In article <151@gipsy.UUCP>, ch@gipsy.UUCP (Christian Huitema) says:
>>	Contrarily to the "usual" (IP - TCP - UDP) protocols, the OSI
>>	architecture is strongly connection oriented. 
>Not really! I always thought TCP was connection oriented. And now, we've
>got a Connectionless Network Protocol (ISO DIS 8473) very similar to IP in
>some ways!

My understanding is that there are two contingents in the ISO standardization
effort: the Telcos are pushing the connection oriented protocols and
the computer scientists are pushing the connectionless protocols.  The
result is that the ISO network layer has both: CLNS for IP style datagrams
and CONS for X.25 style virtual circuits.

If I correctly interpret this, it means that internetworking is suddenly
4 times as complex as it used to be - connection oriented transport protocols
have to be prepared to deal with either CLNS or CONS network protocols,
and connectionless transport protocols have to deal with both also.  IP
makes internetworking a reasonable problem - only datagrams need to be
sent, so there is no state in the internetwork layer.  I shudder to think
of routing a datagram across potentially several networks, some of which
are connectionless and some connection oriented.

The problem is further complicated when you look at the protocols that
fit underneath CLNS/CONS.  For LAN's, it's not a problem, you can use
Ethernet or any number of datagram based networks.  However, for a long
haul network, I understand that X.25 is the only game in town, and that
therefore CLNS will have to be implemented on top of X.25 virtual circuits.
This, of course, defeats the whole purpose of CLNS, which is to cheaply
pass a datagram to an arbitrary host without the overhead of setting
up a connection.  Given these cheap (but unreliable) datagrams, it is
then possible to cleanly construct a reliable transport layer protocol,
ala TCP on top of IP.

I gather you folks in France are more closely tied into what's really
going on than I am.  Is there a nice solution to these problems in the
works, or is it really this big a mess?

	Mark