🚀 go-pugleaf

In article <1993Jan27.115319.21112W@lumina.edb.tih.no>, ketil@edb.tih.no (Ketil Albertsen,TIH) writes:
> Almost any computer networks textbook will spend a page or two stating
> that TCP corresponds to OSI Transport, IP to OSI net, but IP is 
> connectionless while OSI is CO. That's about it - sometimes I wonder
> how they can spend several pages saying nothing more.

Where did you get the idea that the OSI reference model cares whether the
network layer runs CONS or CLNP? There are ISO standards for both and in the US
GOSIP, CLNP is called for. Just because local authorities decide to run CONS
(as most Europeans probably do) is no reason to assume that it is in the
standard.

While there are LOTS of ISO standards that fit in the OSI model, the OSI model
is just that. It describes what each layer does as a general function, not
specific. IP does fit into the OSI model at the network layer. It only lack
blessings as an OSI standard. TCP fits into the transport layer the same way.
(As do the ISO/CCITT approved TP0, TP1, TP2, TP3, and TP4.)

Somewhere the idea has been popularized that OSI means interoperability in some
way. Not so. That requires systems to run matching OSI profiles, like US GOSIP
or UK GOSIP (or both). Otherwise you will get a system running TP0 and TP2
trying to talk to one running TP4 with no success.

To go a step further, there is nothing that prevents running the upper OSI
level over TCP/IP. See RFC1006, and ISODE. And, for that matter, TCP could run
on an ISO network protocol such as CLNP. In fact, the Internet Architecture
Board even recommended exactly that to alleviate the lack of IP address space.

R. Kevin Oberman			Lawrence Livermore National Laboratory
Internet: koberman@llnl.gov		(510) 422-6955

Disclaimer: Don't take this too seriously. I just like to improve my typing
and probably don't really know anything useful about anything.