Iso/Osi

Prelude A long long time ago (I can still remember as Madonna sang) I started to wrote some posts about the network. For those who missed the previous posts, you can read the introduction, the physycal layer and the datalink layer respectively. As a main source I use Computer Networks and TCP/IP Illustrated. In the previous posts I had to go into details about how some parts of the physical layer works but - by going forward through the layers - concepts belonging to separate historical standards - OSI and IP - will intertwine and this entails some troubles from a logical point of view. In this article, I will continue from there by going more practical with some hands-on to better understand this topics. ...

A journey through the network - Layer 2 A month ago I started to wrote some posts about the network. For those who missed the previous posts, the introduction and the physycal layer. For the previous post I had to go into details about how some parts of the physical layer work but, by going forward with the layers, concepts belonging to separate historical standards - OSI and IP - will intertwine and this entails some troubles from a logical point of view. I will try, as far as possible, to keep only the basic concepts of this layer: I also remember that this layer, together with the physical layer, are - at least in part - joined together in what is called the network access layer in the TCP / IP model. As a main source I use Computer Networks and TCP/IP Illustrated. In this article, I will talk about layer 1, the data link layer in the ISO / OSI stack. Enjoy the reading! ...

A journey through the network - Layer 1 Before the Christmas holidays, I wrote an article about the network: yes. The network is that part of computer science that is no longer considered fundamental as it should, and I must admit that I learn it every day at my expense: as an old friend always says to me “the network is the concept on which everything is based, describes how the body works: after that, you can also become a gastroenterologist, but you will always need to know how the body works”. I think he’s right. As I was saying, I wrote an article about that: it’s a sort of overview and technical / historical introduction on the ISO / OSI and TCP / IP protocols. For those who missed the introduction, here the link. Despite my lack of experience, I promised myself, as far as possible, with the little time available, to retrace the various levels of the network from a theoretical point of view without going into too much detail, also trying to identify the most used commands, understand the level at which they operate and the functioning of the parameters supported by them. It took me a lot of time … but finally, the post on level one is ready. As a main source I use Computer Networks and TCP/IP Illustrated. In this article, I will talk about layer 0, the lowest in the ISO / OSI stack. Enjoy the reading! ...

A journey through the network - Introduction During the last year I understood one thing: sooner or later everyone should review network notions, so I decided to start writing articles about network fundamentals. As a main source I would use Computer Networks and TCP/IP Illustrated. In this article, I will talk about two important network architectures: the OSI reference model and the TCP/IP reference model. These two model has opposite characteristics, in particular: ...