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> [OSI's] negatives far outweigh its positives. OSI is not theory, it’s not a framework, it’s not helpful, it’s not a standard, it’s not anything those who use

by kiitos 3y ago

> [OSI's] negatives far outweigh its positives. OSI is not theory, it’s not a framework, it’s not helpful, it’s not a standard, it’s not anything those who use it claim it to be. Anything you teach with the OSI Model can better be taught without it. This is a naive understanding of the OSI model, whose primary virtue is not any specific detail it expresses, but instead its ubiquity. The only way to successfully replace a (clearly entrenched) status quo is to make the positive case for the new thing, which has to be just obviously and significantly better. Pointing out the flaws in the current thing is never convincing, and never a winning strategy.

lmm 3y ago
It's far from ubiquitous though. It breaks down as soon as you enter the real world. It's simultaneously too vague to be useful for talking about specifics and too inaccurate to be useful for talking about generalities.
- kiitos 3y ago
  It's absolutely ubiquitous as a model. It's taught in every CS curriculum in every university in the world. It also doesn't break down in the real world, unless you're being extremely pedantic. Many bits of software don't map cleanly to the defined layers, but we can still talk about the distinction between the network layer vs. the session layer, for example, and get value out of that discussion.
  - lmm 3y ago
    > It also doesn't break down in the real world, unless you're being extremely pedantic. It breaks down if you're trying to do anything at all with it. There are basically two layer boundaries that are useful to talk about in the real world - between Ethernet and TCP/IP, and between TCP/IP and application protocols. The OSI model has 6 layer boundaries but a) neither of them maps cleanly to either of those two real-world buondaries b) no-one knows what the other 4 are (you can kinda-sorta say that the boundary between TCP and IP is one of them, but that isn't the distinction that the OSI says it is either). Depending who you ask you can sort of retrofit it and say that the boundary between Ethernet and TCP/IP is between OSI layer 2 and 3 or 3 and 4, and the boundary between TCP/IP and application protocols is somewhere between layers 4 and 7, which is sort of ok because no-one knows WTF layers 5 and 6 are meant to be. But you're really not getting any value from using the OSI model at that point; it's not telling you anything useful and it's actively getting in the way of understanding what's going on. > we can still talk about the distinction between the network layer vs. the session layer, for example, and get value out of that discussion. Like what?
  - robertgraham 3y ago
    You can't. Nobody knows what the session layer does. Most falsely believe that layer handles sessions.
corethree 3y ago
Ubiquity isn't a necessarily good thing. It depends on the type of person you are for this analogy to work but... Religion is ubiquitous and it is largely just inaccurate made up fantasy stories posing as truth. It's generally not good from this perspective. OSI is religion. And like religion, it is ubiquitous. Is that a good thing? I'm not sure.
- kiitos 3y ago
  OSI is just a model. Like all models, it's wrong. But its ubiquity, and the fact that it's survived the test of time, clearly signal that it is a useful model. And that's as good as models get.
  - Joker_vD 3y ago
    And this specific model is very wrong. It is not useful; it survived mostly because it's useless: slapping an "OSI level X" label on something affects pretty much nothing so sure, you can keep doing that and keep teaching it to people.
  - corethree 3y ago
    Not all models are truly wrong. But I get your point. I think though the author isn't just arguing that the OSI is like your typical "wrong" model. I think he's saying it's a shitty model. It's crap. It's like using Hippocrates four humors to model human health. Yeah that model is wrong just like every model. But unlike every model it's a garbage model. Religion has ALSO survived the test of time, but Jesus Christ coming back from the dead and walking on water is still utter bullshit. Not to get into a religious argument here, but if you're Christian let me know and I'll have to look harder for another analogy. Anyway my point is: Surviving the test of time, Does not mean shit.
    - kiitos 3y ago
      Look, just tautologically, if it was so shitty, we wouldn't be talking about it, because nobody would be using it. You're free to use a definition of "shitty" that doesn't take into account usage or longevity, but that definition is not really relevant except at the theory level.

by kiitos 3y ago

lmm 3y ago

It's far from ubiquitous though. It breaks down as soon as you enter the real world. It's simultaneously too vague to be useful for talking about specifics and too inaccurate to be useful for talking about generalities.

kiitos 3y ago
It's absolutely ubiquitous as a model. It's taught in every CS curriculum in every university in the world. It also doesn't break down in the real world, unless you're being extremely pedantic. Many bits of software don't map cleanly to the defined layers, but we can still talk about the distinction between the network layer vs. the session layer, for example, and get value out of that discussion.
- lmm 3y ago
  > It also doesn't break down in the real world, unless you're being extremely pedantic. It breaks down if you're trying to do anything at all with it. There are basically two layer boundaries that are useful to talk about in the real world - between Ethernet and TCP/IP, and between TCP/IP and application protocols. The OSI model has 6 layer boundaries but a) neither of them maps cleanly to either of those two real-world buondaries b) no-one knows what the other 4 are (you can kinda-sorta say that the boundary between TCP and IP is one of them, but that isn't the distinction that the OSI says it is either). Depending who you ask you can sort of retrofit it and say that the boundary between Ethernet and TCP/IP is between OSI layer 2 and 3 or 3 and 4, and the boundary between TCP/IP and application protocols is somewhere between layers 4 and 7, which is sort of ok because no-one knows WTF layers 5 and 6 are meant to be. But you're really not getting any value from using the OSI model at that point; it's not telling you anything useful and it's actively getting in the way of understanding what's going on. > we can still talk about the distinction between the network layer vs. the session layer, for example, and get value out of that discussion. Like what?
- robertgraham 3y ago
  You can't. Nobody knows what the session layer does. Most falsely believe that layer handles sessions.

corethree 3y ago

Ubiquity isn't a necessarily good thing. It depends on the type of person you are for this analogy to work but... Religion is ubiquitous and it is largely just inaccurate made up fantasy stories posing as truth. It's generally not good from this perspective. OSI is religion. And like religion, it is ubiquitous. Is that a good thing? I'm not sure.

kiitos 3y ago
OSI is just a model. Like all models, it's wrong. But its ubiquity, and the fact that it's survived the test of time, clearly signal that it is a useful model. And that's as good as models get.
- Joker_vD 3y ago
  And this specific model is very wrong. It is not useful; it survived mostly because it's useless: slapping an "OSI level X" label on something affects pretty much nothing so sure, you can keep doing that and keep teaching it to people.
- corethree 3y ago
  Not all models are truly wrong. But I get your point. I think though the author isn't just arguing that the OSI is like your typical "wrong" model. I think he's saying it's a shitty model. It's crap. It's like using Hippocrates four humors to model human health. Yeah that model is wrong just like every model. But unlike every model it's a garbage model. Religion has ALSO survived the test of time, but Jesus Christ coming back from the dead and walking on water is still utter bullshit. Not to get into a religious argument here, but if you're Christian let me know and I'll have to look harder for another analogy. Anyway my point is: Surviving the test of time, Does not mean shit.
  - kiitos 3y ago
    Look, just tautologically, if it was so shitty, we wouldn't be talking about it, because nobody would be using it. You're free to use a definition of "shitty" that doesn't take into account usage or longevity, but that definition is not really relevant except at the theory level.