Are we using TCP/IP or OSI in internet? [closed]

Question

sorry for that question, but i've searched about that topic, and it's not really clear, they say that internet uses tcp/ip but sometimes they say that osi also is used! for example, UDP application, they dont use tcp/ip since it's not a tcp?!

please, can someone make it clear? mean; where is "exactly" OSI is used, and where is "exactly" TCP/IP is used!

Inchworm

Answer 1

The internet is based on TCP/IP which is a "simplified" implementation of the theoretical OSI model. Maybe it's even better to say TCP/IP was inspired by the OSI model, since it does not really match up on closer review.

More info here:

http://en.wikipedia.org/wiki/OSI_model#Comparison_with_TCP.2FIP_model

and here:

http://en.wikipedia.org/wiki/TCP/IP_model#OSI_and_TCP.2FIP_layering_differences

Neptunian

so where is the OSI, where is it used now in 2012? – Inchworm

it is not used at all. OSI is just a theoretical model, it has never been implemented 1:1 in a real world scenario. TCP/IP is an "implementation" of the OSI model. – Neptunian

sorry, but what i cant understand, is that the osi is made after the tcp/ip, so in the logic way, the osi should be based on tcp/ip no? – Inchworm

The OSI model was developed by researchers. It only exists on paper. Afterwards TCP/IP was created by using the principles that were described in the OSI model. TCP/IP in it's various versions is what the internet is based on today. – Neptunian

who was the first, osi or tcp/ip? am confused! – Inchworm

OSI was first, but again it was/is only a MODEL. – Neptunian

OSI was created in 1978, TCP/IP in realy 1970's! so the TCP/IP is after the OSI! it's in french "Le modèle TCP-IP est un modèle qui fut créé dans les années 70 par le département de la défense des états unis d’Amérique, plus précisément par l’agence DARPA (Defense Advanced Research Projects Agency). C’est pour cette raison d’ailleurs que vous le trouverez aussi sous l’appellation « DoD model » pour Department of Defense Model (modèle du département de la défense). Quant au modèle OSI, c’est en 1978 ..." siteduzero.com/tutoriel-3-401755-modeles-osi-et-tcp-ip.html – Inchworm

ok, lets try again. I simplified my answer (which made it slightly incorrect) to make you understand that OSI is just the grand scheme MODEL it is NEVER used as such. To actually communicate you need protocols like TCP/IP or UDP(/IP). The OSI model just tells how these protocols relate to each other and how they are structured conceptually. To get a deeper understanding which how the protocols map to the OSI model (layers) please checkout: tech-faq.com/osi-model.html especially "How Do Real World Protocols Map to the OSI Model?" and "What is the TCP/IP Model?" – Neptunian

I don't understand why people keep claiming TCP/IP came after OSI. TCP/IP evolved directly from the ARPANET programme which was the first to implement it. TCP/IP v4, which is what is in use today on the Internet, was developed at the end of the 1970s and is described in the IETF publication RFC 791 of 1981. The OSI standard was published in 1984. – Sixtyfour

@Neptunian Everything you have written here about the respective timelines is the exact opposite of the truth. Look it up before you perpetrate further errors on this topic. – Brianabriand

Answer 2

When i was searching the answer, even i found it dificult to understand as the answers(even if correct) are not exactly matching the doubts in the question.

The question is actually regarding the differnce between OSI model and TCP/IP model and not TCP/IP protocol which the answers are based on. A person who doesn't know the difference will get confused or not get satisfied with the answer at all. I thought i will try to answer this question with little more explanation.

Sorry for all the above blah blahs .. Here is the answer :

TCP/IP model was formed by DoD( Department of Defence ) which came almost 10 years earlier than OSI model and is defined with 4 layers as TCP and IP are the two protocols just like FTP, UDP, SNMP, SMTP, Telnet, etc. It was also called Internet Model. But i know the name itself is confusing. The layers were not defined properly as they were just based on protocols.

But after some research the layers were again got redfeined and OSI model shows us 7 layers which should be the way of implementation of any communication.

TCP/IP model had lots of issues like Transport Layer doesn't guarantees the delivery of packets, doesn't have a seperate Presentation layer, replacing protocol is not easy as they are not hidden unlike OSI model and you bet thats how OSI model came into existence

Now as both are just models, in real world we just worry about protocols as thats how the things are implemented. So OSI model is a reference on how we use internet today and not the TCP/IP model.

Substantial

Answer 3

The ISO/OSI model is, essentially, a theoretical construct.

TCP/IP is roughly an implementation of it.

Tolerable

sorry, but tcp/ip came before osi, osi is made after the tcp/ip – Inchworm

I see no contradiction here. – Vintage

TCP/IP is roughly an implementation of s own model. Not of the OSI model. – Brianabriand

Answer 4

TCP/IP or UDP/IP are just protocols of Internet. They are in the 4th Layer of OSI. TCP or UDP are used to determine what kind of connection is to be established whether Connection-Oriented or Connection-Less.

Connection Oriented which uses TCP/IP protocol is used when there is a need to establish a session and where lost packets have to be retransmitted if lost like when you use email, you dont want to send a mail with uncertainty of whether the mail will reach its destination or not and moreover with uncertainty of sending incomplete mail with lost packets.

Connectio-Less which uses the UDP/IP protocol is used when you dont want waste time on establishing a connection and you dont want to retransmit the lost packets as the latest packet is more necessary to reach the destination like when using chat, you dont want to resend the old packets or data later or else it will be like you are talking on some other topic and the earlier packet reaches later out of nowhere. Same can be said for buffering of a video.

Hope it clears your doubt. For further queries google the uses of TCP/IP and UDP/IP and do go through the OSI model once and try to understand what each layer does and there contribution in transmission of data packets.

Topsyturvydom

so internet and what am using now, for example using stackoverflow, or browsing youtube, my pc and the server of youtube or SO are using tcp/ip and not osi?! – Inchworm

They all are using OSI model within which TCP/IP or UDP/IP resides. Its like Oxygen = TCP or UDP and Air = OSI model. So if you are breathing, can you say that you are only using Oxygen and not using Air or other way around? – Topsyturvydom

am confused here :D something should use only one definition and must avoid ambiguities especially in computer science? so we must choose only one: tcp/ip or osi to define what internet uses? – Inchworm

Hey Abdel, everything is related to each other. There is nothing in Computer Science that works independently or alone. Actually the whole engineering is inter-related. These are not ambiguities, its the connection. – Topsyturvydom

but there are some cases where it must have hte ONE to ONE relation ^_^ – Inchworm

Answer 5

The Internet uses IP v4, which is part of the TCP/IP model.

The TCP/IP model was evolved directly from the US Defense Department's ARPANET programme. The first TCP/IP version was determined in 1974. The version 4 specification was published in 1981 and declared standard for US military use the following year:

https://en.wikipedia.org/wiki/Internet_protocol_suite

The OSI model was defined by the ISO and published in 1984.

Therefore, TCP/IP is not an implementation of OSI, although they are similar. Both OSI and TCP/IP are reference models. TCP/IP is an older reference model, and OSI model is a new standard that other models often don't fit neatly into.

https://en.wikipedia.org/wiki/OSI_model

Sixtyfour

Answer 6

OSI model is a reference model to indicate how the communication between the various devices takes place. While TCP/IP is not a model,it is a set of protocols that governs the flow of information across the networks..Conceptually it is based on the OSI model only that is why sometimes few people term it as TCP/IP model also.

Speciosity

tcp/ip model is not based on OSI, it is way before the OSI was launched. – Bath

Answer 7

The International Organization for Standardization (ISO) created the Open Systems Interconnection (OSI) reference model as a framework for defining standards for connecting computers. Released in 1984, the model was an attempt to get the entire world to think about computer networking in same way, and was to act as a first step towards standardizing the actual protocols that people used to communicate via computers.

The Defense Advanced Research Projects Agency (DARPA) is an agency of the United States Department of Defense responsible for the development TCP/IP Model. The TCP/IP Model is sometimes called the Internet Model or less often the DoD(United States Department of Defense) Model.

The TCP/IP model describes a set of general design guidelines and implementations of specific networking protocols to enable computers to communicate over a network.

Verbatim

The TCP/IP model predates OSI by some ten years. – Brianabriand