Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!voder!pyramid!csg From: csg@pyramid.pyramid.com (Carl S. Gutekunst) Newsgroups: comp.protocols.iso Subject: Re: How to implement OSI protocols? Message-ID: <155284@pyramid.pyramid.com> Date: 13 May 91 15:59:13 GMT References: <890@hwsw.gedas.de> Organization: Pyramid Technology Corp., Mountain View, CA Lines: 32 >It means, everybody is free to implement the protocols as he likes. No, the language and operating system bindings can be done however you like. (And in fact, they are done lots of different ways.) The protocols, however, are defined by the standards. Various industry groups (including X/Open and UI) are busily working to define bindings. This is a very good thing, IMHO. But it is a very different thing from defining protocols. I just reviewed two different application programmer interfaces to X.25. They were quite a bit different, and have consider effect on the architecture of the programs that would use them. But the X.25 packet- layer protocol is unaffected. >- each protocol is one seperate process (I know what Comer thinks about this) The preferred implemention in commercial UNIX these days is each protocol (or other logical division) in a streams module, in the kernel. Applications chose the pieces that they need, and string them together. For example, an X.400 '84 RTS would push an appropriate transport and the session layers; an X.400 '88 RTS would also need to push the presentation layer and ACSE. >These are just some ideas which came to my mind reading OSI books and being >frustrated with my daily work administering our local TCP/IP net and the >connection to the Internet. Um, if you are frustrated administering a TCP/IP network, you ain't seen nothing yet. Present day OSI stacks require vastly more administrative work, as well as far more network understanding, than any modern TCP/IP network. We are a long way from even designing (let alone implementing) the tools that will make the OSI stack easily managable.