3 ms·

This is wonderful material. But admittedly, I am a bit lazy on reading to the part I want: what is a good model, or set of models, I should re-educate myself wi

by NBJack 3y ago

This is wonderful material. But admittedly, I am a bit lazy on reading to the part I want: what is a good model, or set of models, I should re-educate myself with to correct what I was taught?

tptacek 3y ago
Ethernet, IPv4, TCP, and HTTP; what functions do each provide, how is each coupled to its neighbor, and what are the viable alternatives in the design spaces of each? Part of the OSI layering model was I think meant to get people's brains wrapped around the dynamics of packet switching networks, which were once a novelty and are now just part of the air we breathe. Then, read: https://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.pdf https://web.mit.edu/Saltzer/www/publications/endtoend/endtoe...
- thayne 3y ago
  I would probably add TLS in thereas an optional layer between TCP and HTTP. But http/3 and quic complicates things because it kind of blends the tcp, tls, and http layers together.
  - KirillPanov 3y ago
    Layer 4 is the lowest layer of the OSI model that isn't packet-based (i.e. can handle messages of arbitrary size). IMHO that's the highest layer of the OSI model that is useful. After that it's various ways of tunnelling streams inside of streams.
    - fanf2 3y ago
      That’s not true, though: the OSI model has connection-oriented services at the lower layers too.
  - deleted 3y ago
    [deleted]
- robertgraham 3y ago
  It's wrong to think of them as different functions of the same network. Instead, they are differnet networks. Ethernet and the Internet both provide the function of forwarding packets through a network to the target destination address. The MAC protocol and IP protocol provide the same theoretical function. Where they differ is that Ethernet was designed to a be a local network, whereas the Internet is designed to be an internetwork. All it demand from local networks is that they get packets from one hop to the other. Ethernet does this for the Internet, but so do carrier pigeons. The same is true for HTTP. Instead of thinking of it as a component of the network, think of it as something that rides independently on top of the network. In a hypothetical future whe we've replaced the Internet with some other technology, the web would still function.
  - KirillPanov 3y ago
    > Where they differ is that Ethernet was designed to a be a local network, whereas the Internet is designed to be an internetwork. Then your criticism of the first three OSI layers is merely that they should be named "point-to-point", "local", and "inter". I can agree with that criticism. But I can't agree with needing 239 pages to convey it.

by NBJack 3y ago

This is wonderful material. But admittedly, I am a bit lazy on reading to the part I want: what is a good model, or set of models, I should re-educate myself with to correct what I was taught?

tptacek 3y ago

Ethernet, IPv4, TCP, and HTTP; what functions do each provide, how is each coupled to its neighbor, and what are the viable alternatives in the design spaces of each? Part of the OSI layering model was I think meant to get people's brains wrapped around the dynamics of packet switching networks, which were once a novelty and are now just part of the air we breathe. Then, read: https://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.pdf https://web.mit.edu/Saltzer/www/publications/endtoend/endtoe...

thayne 3y ago
I would probably add TLS in thereas an optional layer between TCP and HTTP. But http/3 and quic complicates things because it kind of blends the tcp, tls, and http layers together.
- KirillPanov 3y ago
  Layer 4 is the lowest layer of the OSI model that isn't packet-based (i.e. can handle messages of arbitrary size). IMHO that's the highest layer of the OSI model that is useful. After that it's various ways of tunnelling streams inside of streams.
  - fanf2 3y ago
    That’s not true, though: the OSI model has connection-oriented services at the lower layers too.
- deleted 3y ago
  [deleted]
robertgraham 3y ago
It's wrong to think of them as different functions of the same network. Instead, they are differnet networks. Ethernet and the Internet both provide the function of forwarding packets through a network to the target destination address. The MAC protocol and IP protocol provide the same theoretical function. Where they differ is that Ethernet was designed to a be a local network, whereas the Internet is designed to be an internetwork. All it demand from local networks is that they get packets from one hop to the other. Ethernet does this for the Internet, but so do carrier pigeons. The same is true for HTTP. Instead of thinking of it as a component of the network, think of it as something that rides independently on top of the network. In a hypothetical future whe we've replaced the Internet with some other technology, the web would still function.
- KirillPanov 3y ago
  > Where they differ is that Ethernet was designed to a be a local network, whereas the Internet is designed to be an internetwork. Then your criticism of the first three OSI layers is merely that they should be named "point-to-point", "local", and "inter". I can agree with that criticism. But I can't agree with needing 239 pages to convey it.