TCP/IP explained is much more straightforward than you might think. The term stands for “Transmission Control Protocol/Internet Protocol” and actually refers to a whole suite of protocols which includes these two among many others. All together, the TCP/IP suite is the foundation on which the Internet architecture is built on. So, how can something as complicated as the Internet be standardized in a coherent and consistent way?
The basis which led to the formulation of the TCP/IP suite is a previous standard published by IEEE back in 1979, the so-called ‘ISO/OSI’ standard. According to it, in order to be able to support a varied array of devices, the structure of a protocol suite had to be organized in several ‘layers’, one on another, and in such a way that each layer saw the rest of the suite as a ‘black box’ only accessible through a few functions that would let the layer do their job by processing an input and sending the output to one of the adjacent layers.
The concept of the ‘black box’ soon turned out to be very well thought, as it let layers process input independently from any of the others. For instance, a lower layer could receive information from two different devices, process them separately, and then elaborate the data properly to be able to send it to the upper layer, which wouldn further process the data regardless what device it came from.
ISO/OSI defined seven different layers:
1. Physical: the binary transmission traveling through a mean of transport;
2. Data link: physical addressing of peripherals (MAC & LLC);
3. Network: routing and high-level addressing (IP);
4. Transport: end-to-end connections (TCP, UDP);
5. Session: communication between different hosts;
6. Presentation: defines the way data is represented and encrypted;
7. Application: the final process to the terminal application.
However, TCP/IP only picked up four of those (merging the last 4 levels together, as it soon became evident that there was no practical need to have them separated). When a packet (that is, a small bulk of information, usually between 64 and 1500 bytes long) is created from level 4-7, a header is added in front of it, and then it’s passed to the lower level, which, in turn, adds its own header in the front, until it reaches the first, physical layer. At this point, information is passed back at level 2, which uses the header that was added by the sender’s second layer as the ‘input’ to compute their functions (mostly error checking and routing) and pass it to the higher level, until it reaches the intended receiver.
Of course, all four levels in TCP/IP need to work in order for the data to be successfully transmitted over the Internet, but there is one protocol that is usually considered to be the fundamental one, as it’s the only available one for the third level, and therefore manages to provide a higher level of abstraction, even in its simplicity: that is the IP protocol, the one Internet routers are made to process. Routers constitute the bulk of the Internet, as they are interconnected ‘nodes’ that are able to apply complex mechanisms through which they are able to decide where to forward a received packet in order to transmit it as quickly as possible.
In general, one of the funding principles of the TPC/IP suite is that complexity should be put as much as possible on the hosts (terminals), rather than the nodes of the network: this is essential in a packet commutation network to ensure fast elaboration and transmission time, therefore following the exact opposite strategy of the telephone network, in which all the complexity is put on the network itself to be able to build very cheap terminals (telephones).
Tags: internet protocol, tcp/ip, transmission control protocol
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May 27th, 2008 at 11:09 am
Good info. my networking terminology stops at LAN. the only time I set up a LAN was to have a huge Quake death match.
May 27th, 2008 at 7:56 pm
Thanks for the technical yet simple explanation on the various protocols. I guess with rapid advancement in more and more user-friendly internet technology, such detailes technological information may not be necessary and relevant in future. Anyway it is good to know.
May 30th, 2008 at 2:47 pm
Heh thanks for this, it was nice and easy to understand. These sorts of things confuse me-any technology terms, for that matter. It’s good to know, but hard for people to learn about on their own. Thanks again.
June 4th, 2008 at 3:58 am
Interesting information. My understanding of IP was much more simple and basic and yet, the understanding of how the layers communicate with each other makes it easier to appreciate the process rather than complicating it. Last year I read about a lady from Sweden boasting of the fastest internet connection around the world. The speed was 40GB per second and it could download a dvd in just 2 seconds. Wonder if we are moving towards a world where the television will become redundant.
June 10th, 2008 at 10:26 am
Next lesson: The IP. That’s when it’ll get complicated with the ip addresses and ip configurations from LAN to WAN to the internet.
And vttop, I just had to look up that 40GB and it turns out it was in gigabits and not gigabytes (silly me) but still. Wow! Apparently it’s just a demonstration but it did demonstrate that it’s possible.
June 12th, 2008 at 7:00 am
Again another nice article. TCP/IP isn’t really difficult to understand but it took me a while before I understood how the different layers interact with each other. All understanding the different components of the TCP header wasn’t really easy to understand and took me a while to take it all in.
June 12th, 2008 at 10:47 am
I wish you could post more of technical posts like this as it was very informative and interesting. i have learnt about its working previously but to be frank, i never understood that. Now it has been made simple by you and thanks a lot for this. I expect more posts of this kind.
June 15th, 2008 at 10:42 pm
Articles like this are really helpful because as things get easier and more sanitized for the public’s use, then less and less people really know the technical stuff. It’s always good to be versed in the basics.
June 16th, 2008 at 12:11 pm
Well typically you do not need this type of information unless you are directly working with TCP/IP but it is good to know some things about it when you are dealing with or working with computers in general. I would like to see more articles such as this as well. Maybe I will try to see about submitting an article to the site.
June 23rd, 2008 at 1:34 am
This is my first time to read an article about TCP/IP, all this time I thought these are just settings on your computer for changing your IP address. Maybe I need to read some more articles about it to fully understand its function and importance.