Came across some of my old CCITT/OSI books. I think the theory of the OSI stack is still taught in the classroom, but I suspect a lot of the lore will be forgotten.pic.twitter.com/ie2vCVxfww
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ASN.1 had optional formatting schemes...for examples you could implement strings as null-terminated and/or length/data format. X.400 servers built in Germany and France were unable to exchange messages, because they each close a different string format.
In the internet, IP is the protocol for sending data packets, but without guarantee of delivery. The TCP protocol established a reliable data stream using IP...it put packets in order, tossed out duplicates and asked for re-transmission of missing packets.
In OSI, the analogue to TCP was called TP4. Early implementations of that complex protocol were so slow, it took longer to send one packet than the timeout interval that TPC used to give up and close a connection.
OSI was an expensive failure; not only in terms of the cost of the specification and development, but in terms of the opportunity cost of delaying the deployment of the internet in Europe and Japan. Trust in standards committee was sullied by the project.
Fortunately, all of this happened well before 1995 when the internet became a mass media used by regular citizens. So I don't think the theory and experience learned from OSI were a disastrous waste.
And while we are talking about fumbling the future, I should also say something about AT&T, where I worked. The Army once asked them to take over and manage the ARPANET, and the company declined.
Even while I was there in the 1980s, there was hostility and derision of the idea of packet switched networking. The 1127 research lab (where UNIX was created) built their own circuit-switched computer network they called Datakit.
The lab I was in (1138) was something of a pariah, because we used ethernet and ran TCP/IP and Berkeley UNIX on our computers. We also got scolded by the communications-workers union, because we installed the ethernet cable ourselves.
AT&T's physical network was impressive technology: an all-photonic network with lithium-niobate crossbar switches, laser amplified undersea cables, and lossless token ring networks that serviced cities.
I saw a presentation of this system that included making fun of TCP/IP and laughing at the idea that AT&T would support the internet. Ironically, the internet still runs on top of that photonic network infrastructure.
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