How does data flow in the TCP/IP model?

Question

Basically I'm looking for something along the lines of how data flows through the TCP/IP model from the source and destination computer - here is an example of the OSI model I did, but I can't find anything easy and simple like the OSI, anyway without further adieu here is an example;
• The user requests data to be sent over the network; the application layer approves and sends the data over to the presentation layer.
and so on and so on for each other layer in the OSI model.
Thanks!

Answer 1

Check this Wiki page out:



http://en.wikipedia.org/wiki/TCP/IP_model



Scroll down to the section "Layers in the Internet protocol suite" and you have your answer.

Answer 2

They work the same way. The TCP model is basically the same as the OSI model, it just condensed the Application, Presentation, and Session layers in to one layer called the Application layer. That and the Application layer in TCP is layer 1 where as in OSI the Physical Layer is layer 1.



Keep in mind, these are abstract models, there is nothing in the computer that says this is application layer stuff, data link layer stuff, etc. If you were able to come up with an example on your own for with the OSI model, you can do with the TCP model as well.



Also, I've worked with 20 or 30 vendors/manufactures of network solutions from around the world, I've yet to come across one that described things with the TCP model.

Answer 3

The user requests data to be sent over the network;



In an Email Application:



in the Email client you press send (application Layer) and sends the data into a format, this will be a *.eml (presentation layer) the presentation has the data (email) to send so will now request a socket to the Communication Layers (Session Layer) This layer packs up the file and adds sender and destination info into a network packet to send across the internet/WAN to the (transportation Layer) who request transmission intervals, sets up CHAPS, flow control and encryption until the packet reaches its destination which is a Modem (Network Layer) here IP address resides and the packet is decapsulated into a Network frame and if more then one device on the network a router is used which handles the Network Address Translation and either acts as or sends the data frame to a switch (Data Link Layer) The switch or router sends the raw data via wifi/cable (Physical Layer) to the intended machine who receives it on thier Session Layer which passes (decapsulate) it the Presentation layer and to the receipients Application Layer.



It works via encapsulation (going down) and decapsulation (going up)...



Not always is this process the same as at times routers are not used... Network Layer 3 switches are used which functions as routers or no routers or switches at all are used.

TCP is at times not used and its counter part UDP is used which sends Datagrams and not Packets and doesnt use tight security as TCP.