So let's discuss the "OSI Model". There's no such thing. What they taught you is a lie, and they knew it was a lie, and they didn't care, because they are jerks. You know what REALLY happened when the kid pointed out the king was wearing no clothes? The kid was punished. Nobody cared. And the king went on wearing the same thing, which everyone agreed was made from the finest of cloth.

The OSI Model was created by international standards organization for an alternative internet that was too complicated to ever work, and which never worked, and which never came to pass. Sure, when they created the OSI Model, the Internet layered model already existed, so they made sure to include today's Internet as part of their model. But the focus and intent of the OSI's efforts was on dumb networking concepts that worked differently from the Internet. OSI wanted a "connection-oriented network layer", one that worked like the telephone system, where every switch in between the ends knows about the connection. The Internet is based on a "connectionless network layer". Likewise, the big standards bodies wanted a slightly different way of how Ethernet should work, with an LLC layer on top of Ethernet. That never came to pass. Well, an LLC layer exists in WiFi packets, but as a vestigial stub like an appendix. So layers 1 - 4 are at least a semblance of reality, incorporating Ethernet and TCP/IP, but it's layers 5 - 6 where is goes off the rails. There's no Session or Presentation Layer in modern networks. Sure, the concepts exist, but not as layers, and not with the functionality those layers envisioned.

For example, the Session Layer wanted "synchronization points" to synchronize transactions. Their model never worked, and how synchronization happens on the Internet is vastly more complex, with pretty much everybody designing their own method. Another example, is how Google does Paxos synchronization at scale is a big reason for their success. It's an incredibly tough problem for which it's impractical to create a standard. In any case, you wouldn't want it as a "layer". Sure, HTTP has "session cookies" and SSL has a "session" concept, but that doesn't make these "session layer" protocols.

The OSI Presentation Layer (layer 6) is even more stupider. It was based on dumb terminals connected to mainframes. It was laughably out-of-date before it was even created. Back then, terminals needed to negotiate control codes and character sets. It's not simply "dumb terminals", it's the fact most everyone was still stuck on the concept that computer networks were for human-computer communications, rather than computer-computer communications. The OSI Model they teach is a retconned (retroactive continuity) one that just teaches the TCP/IP model and calls it the OSI Model, and does major handwaving over the non-existent Session and Presentation layers.

I suppose "OSI Model" can be justified if everyone taught the same thing, if it were all based on the same specification. But it isn't. Everyone makes up their own version, like which where to put SSL. (The correct answer is "Transport Layer", btw). As for the popular question "in which layer does encryption belong?", the correct answer is "all the layers". And then some.

OSI is outdated, the four layer model is what is being used now. Because that is what the course I got on Stanford is using.

SegFault:
OSI is outdated, the four layer model is what is being used now. Because that is what the course I got on Stanford is using.

EvilSec where did you run to? Miss alot o. Haba, the only hacker I know.

stanliwise:
EvilSec where did you run to? Miss alot o. Haba, the only hacker I know.

Hahaha! Stanliwise the badass coder!
Took some time off bro... I also lost your number a long time ago, is that your group still up?

EvilSec:

Hahaha! Stanliwise the badass coder!
Took some time off bro... I also lost your number a long time ago, is that your group still up?

The group isn’t active any more like b4 o. How you come dey roll na. How is coding

stanliwise:
The group isn’t active any more like b4 o. How you come dey roll na. How is coding

Sadly, I barely code anymore these days... What about you?

stanliwise:
EvilSec where did you run to? Miss alot o. Haba, the only hacker I know.

Wow a hacker. First time seeing one.

SegFault:

Wow a hacker. First time seeing one.

That can't be true.

EvilSec:

That can't be true.

Honestly bro. I just started programming last year (though I've gone far) so I don't know many hackers plus I'm a loner (it's like a disease or something).

SegFault:

Honestly bro. I just started programming last year (though I've gone far) so I don't know many hackers plus I'm a loner (it's like a disease or something).

I'm sure you've not gone far with you quoting yourself telling us how far you've gone. I guess you've only done some cool stuffs.

Bahat:


I'm sure you've not gone far with you quoting yourself telling us how far you've gone. I guess you've only done some cool stuffs.

I'm learning CS on my own too so what's my business with "cool stuff" (if you are talking about websites and all those normal stuff developers do count me out). The projects I am currently working on are compilers for two new languages, one is a procedural language, with template functions, coroutines, and has a little memory safety (which C lacks greatly). The second uses a register based VM (like the Dalvik VM, don't like stack based VMs), has a garbage collector, is object oriented, uses templates, multithreaded programming, coroutines e.t.c. Though I am kind of in a hook because my laptop spoilt last year and I have been using my phone to learn and build these projects, with termux help though

SegFault:

I'm learning CS on my own too so what's my business with "cool stuff" (if you are talking about websites and all those normal stuff developers do count me out). The projects I am currently working on are compilers for two new languages, one is a procedural language, with template functions, coroutines, and has a little memory safety (which C lacks greatly). The second uses a register based VM (like the Dalvik VM, don't like stack based VMs), has a garbage collector, is object oriented, uses templates, multithreaded programming, coroutines e.t.c. Though I am kind of in a hook because my laptop spoilt last year and I have been using my phone to learn and build these projects, with termux help though

Yeah that's part of what I meant by cool stuff with those compiler constructions your doing. Next is to write an os probably with another approach different from what open source and Others that's have done it in the past. Mind you carisma has a programming language of his own called "simple language". So bro you doing nothing new but reinventing the wheel. If you're bored you can start hacking the Linux kernel or bsd kernels. Termux does nothing really powerful I guess you can do some function hooking on kernel but that's gonna be though with the recent memory protection in place. Quote me if am wrong.

SegFault:
OSI is outdated, the four layer model is what is being used now. Because that is what the course I got on Stanford is using.

OSI is just used to teach , TCP/IP is the standard that is used. OSI was never widely used or adopted .

Bahat:


Yeah that's part of what I meant by cool stuff with those compiler constructions your doing. Next is to write an os probably with another approach different from what open source and Others that's have done it in the past. Mind you carisma has a programming language of his own called "simple language". So bro you doing nothing new but reinventing the wheel. If you're bored you can start hacking the Linux kernel or bsd kernels. Termux does nothing really powerful I guess you can do some function hooking on kernel but that's gonna be though with the recent memory protection in place. Quote me if am wrong.

I can't ever dream of hacking Linux kernels though I want to learn that so bad but man, remember I can't use the Sudo commands or activate the superuser because of the damned protections in place. Yah termux can't do anything powerful unless you root your phone (get the su binary into the root directory somehow) and I need a laptop for that so I just have to manage. Though I am learning a little about Operating Systems. I'll do some research on this function hooking you speak of.

SegFault:

I can't ever dream of hacking Linux kernels though I want to learn that so bad but man, remember I can't use the Sudo commands or activate the superuser because of the damned protections in place. Yah termux can't do anything powerful unless you root your phone (get the su binary into the root directory somehow) and I need a laptop for that so I just have to manage. Though I am learning a little about Operating Systems. I'll do some research on this function hooking you speak of.

hmmm God is your strength.

spoilerx:


OSI is just used to teach , TCP/IP is the standard that is used. OSI was never widely used or adopted .

Yah read about it. The OSI was a huge failure and packed dumb and unnecessary layers like the presentation layer into its structure, ISO and their rush to standardise everything. It's pitiful that some engineers still use it

SegFault:

Yah read about it. The OSI was a huge failure and packed dumb and unnecessary layers like the presentation layer into its structure, ISO and their rush to standardise everything. It's pitiful that some engineers still use it

Q: define the Session and Presentation layers
A: Levels 5 and 6 sound theoretical and silly, I'm going to pretend they don't exist.

Correct!

I hope we can finally get rid of the Session and Presentation layers that never really existed but which every student had to learn.

So "What is the OSI Model?" It's the fact that the local network is independent from the Internet, and the Internet is independent of the applications that run on top of it. It's the fact you can swap WiFi for Ethernet, or IPv6 for IPv4, or Signal for Whatsapp.
When we eventually move to IPv7, we won't need to upgrade Ethernet switches. Ethernet and WiFi have no clue what are doing on top of them. Ancient alternatives like XNS or Novel or NetBEUI also work fine on the latest 802.11ax/WiFi6 router you just bought. There are a few more subdivisions. Layer 1 (Physical) gets the raw bits transmitted on the wire (or into air). Layer 2 (Link) gets packets across your local network to the next router. Layer 3 (IPv4/IPv6) gets packets from one end of the Internet to the other. Layer 4 (TCP/UDP) gets packets to one of many apps running on your machine to one of many apps running on the server. It may also retransmit lost packets. Layer 7 consists of a bunch of different protocols that services those apps.

EvilSec:

Q: define the Session and Presentation layers
A: Levels 5 and 6 sound theoretical and silly, I'm going to pretend they don't exist.

Correct!

I hope we can finally get rid of the Session and Presentation layers that never really existed but which every student had to learn.

So they still teach that crap. How funny, like I was asking myself while reading a networking and socket programming book what is the need of those.

EvilSec:
So "What is the OSI Model?" It's the fact that the local network is independent from the Internet, and the Internet is independent of the applications that run on top of it. It's the fact you can swap WiFi for Ethernet, or IPv6 for IPv4, or Signal for Whatsapp.
When we eventually move to IPv7, we won't need to upgrade Ethernet switches. Ethernet and WiFi have no clue what are doing on top of them. Ancient alternatives like XNS or Novel or NetBEUI also work fine on the latest 802.11ax/WiFi6 router you just bought. There are a few more subdivisions. Layer 1 (Physical) gets the raw bits transmitted on the wire (or into air). Layer 2 (Link) gets packets across your local network to the next router. Layer 3 (IPv4/IPv6) gets packets from one end of the Internet to the other. Layer 4 (TCP/UDP) gets packets to one of many apps running on your machine to one of many apps running on the server. It may also retransmit lost packets. Layer 7 consists of a bunch of different protocols that services those apps.

Ipv7 nawa for the tech world thought 128 bits is more than enough (ipv6)

here is the video i did for you guys on termux

https://www.youtube.com/watch?v=9rzcwHTGc7A

SegFault:

So they still teach that crap. How funny, like I was asking myself while reading a networking and socket programming book what is the need of those.

I forgot most of those things I read on networking and worked with but isn't those two sessions working with web technology Practically.