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0 pointschuckadams1y ago0 comments

Wow, you're not kidding about book-length: at 246 pages, that's an epic takedown. Learning all kinds of other things about networking along the way, though.

I do remember all nine layers of the OSI stack though: physical, data link, network, transport, session, presentation, application, financial, political.

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kazinator1y ago

But we freakin have those layers now. Above TCP/IP there is SSL, and then about that https, and within that there's some JSON RPC or whatever.

The first few OSI layers are fairly readily identifiable in TCP, IP and Ethernet, and some of the rest are built by applications.

kragen1y ago

Having just skimmed X.225 thanks to OhMeadhbh (https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-X.22...) I think Graham is correct that we don't have anything similar to the OSI "session" layer in the stack you're talking about; although the ARPANET TELNET protocol does have a lot of the same functionality, there's nothing analogous in SSL+https+JSON+RPC. I'm guessing the same is true of the "presentation" layer, but I'm certainly open to hearing why you think otherwise, if you do.

Also, if you happen to be familiar with X.225 (or read it following my prompt above), I have some questions in https://news.ycombinator.com/item?id=41789004!

Graham makes a good argument that, although there are some promising analogies between the physical/data-link/network/transport layers and the PHY/MAC/IP/TCP layers of TCP/IP over Ethernet, the model is overall a very poor fit even at those layers; it's better to not try to decompose network stacks into a predetermined set of layers, because the actual set of layers used is variable depending on the application and the environment.

fanf21y ago

BTDTGTTS https://shop.isc.org/collections/shirts/products/osi-9-layer...

chuckadamsOP1y ago

I can't claim to have BTDT, but I did get the T-shirt. That's how I learned them :)

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