TCP/IP Stack Tutorial

Besides the OSI model there was another organization that created a similar reference model which never became quite as popular.

When I’m talking about “not popular” I mean the TCP/IP stack model isn’t used often as a reference model…when we talk about layers, people always refer to the OSI model. On networks nowadays we use TCP/IP all the time…

However if you are studying for Cisco CCNA you’ll need to know what it looks like. It’s called the TCP/IP stack and it’s similar except some of the layers are combined and have different names. Here’s what it looks like:

TCP/IP Stack

As you can see the upper three layers are now combined to the “Application layer”. The network layer is called the “Internet” layer and the bottom 2 layers are combined into the “Network Access” layer.

Here’s a comparison between the two models:

TCP/IP Stack vs OSI Model

Basically it’s the same idea, same model except with some layers combined and different names.  The physical and data link layer are combined into the network access layer. The network layer is now the internet layer and the session, presentation and application layer are combined into a single application layer.


Forum Replies

  1. Actually the TCP layer contains port data, encompassing the transport and session.

  2. Hey Rene. Please help me here. I’m getting confused with OSI and TCP/IP. From Wendell Odom Book it says TCP/IP in the model being used in networking while OSi is just used for referencing but on the above article you are saying TCP/IP was never popular and OSi is the one being used.

  3. Hi Joel,

    The OSI model and TCP/IP stack are both “theoretical” models to describe the different layers of networking.

    IP (or IPv6) and TCP are used everywhere but when we talk about the different layers, normally everyone talks about the 7 layers of the OSI model and not the 4 layers of the TCP/IP stack.

    Does that make sense?


  4. Hi,

    I was thinking that OSI is just a reference model, a blue print. TCP/IP model is an implementation of current internet architecture.
    Am I wrong?

    Durga Prasad.

  5. Durga,
    OSI and TCP/IP are both models, and TCP/IP is a currently implemented model. An interesting fact is that there was, at one time, an actual OSI protocol that followed the 7 layer model of OSI. The OSI protocol (obviously) lost out to TCP/IP.

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