TCP/IP model layers explained | Network protocols

TCP/IP model to standardize computer networking it’s the same description as the OSI model while widely referenced isn’t used in the real world the TCP/IP model however is the real deal thankfully is not that different.


Here is the TCP/IP model four simple layers, application, transport, internet, and link and just like the OSI model it’s numbered from the bottom up but the direction depends on if you’re sending or receiving traffic.

the original model but it has been updated here is the brand new freshly designed model on an extra layer and one renamed layer that’s it.

The like layer has been split into data link and physical and the internet layer has been renamed the network layer, it gets even better when we compare the TCP/IP model to the OSI model.


Now if you remember the OSI model has seven layers compared to our five here but when you look at it you’ll notice the application presentation and session layers are just as application layers in the TCP/IP model.

all the other layers line up nicely which is great because we should already because know the concept of how this works so about the protocols and devices at each layer at the application layer we have application protocols such as HTTP, FTP, and SMTP.


The two most common transport protocols are TCP and UDP port numbers are also added here on the network layer we have this internet protocol or IP Routers also operate at this layer.

The data link layer contains protocols such as Ethernet switches typically operate at this layer, although you can get layer 3 switches that have some routing capabilities.

Finally, we have the physical layer think of everything we can touch and feel here think like cables and network interface cards.

So while we send data each layer will add its bit of information this process is called encapsulation if we hit the physical layer the data is transmitted over to those receiving devices then starts to decapsulate the data.

Decapsulation process


We start with our application data at layer 5 this is then passed down to the next layer where the transport information is added let’s say is a TCP header each time header is added this will contain specific information.

For example, a TCP header will contain things like some source and destination port number sequence numbers and a few more bits from the information.

Network layer where we add the IP header will contain the source and destination IP address as well as some other bits of information.

Data link layer here we add not only a header but a trailer as well the header contains main lead the destination and source MAC address and the trailer contains some error checking information that.

The receiving side can check and make sure the data has been received correctly. Once this data hits the physical layer it is physically transmitted.

Encapsulation process

It’s important to note that in each stage the data has a specific name by layer five the data is called well it’s just called data in this stage. Once the transport information should be added it’s now called a segment.

Joining the network layer information makes our segment a packet and finally, once we add our data link information that packet becomes a frame.

Now one data has been transmitted the receiving computer decapsulates the information it will check the destination MAC address for that frame and if the frame is destined for our computer it’s processed further.

The computer then checks the IP information off the packets again if the packet is destined for our computer is processed further. This transport information is read and the application data is sent to that receiving application.

So that’s for the TCP/IP model after looking at the OSI model.

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