Ethernet and TCP/IP - What is the Difference?

(image credit Pexels)

It’s all about communicating and moving data from point A to point B.  

They exist at different layers of the OSI model.  

TCP is a protocol and so is IP; the main protocols of the internet.   

Ethernet rules the physical layer.

TCP is Transmission Control Protocol. 

IP is Internet Protocol.

Back to basics, there are 7 layers of the OSI model.   (Most of us learned this mnemonic- Please Do Not Throw Sausage Pizza Away.)  Please see this diagram so you can follow:
OSI and TCP/IP Model

1.     Physical—this is where Ethernet lives. 
2.    Data Link—this is where MAC addresses live
3.    Network—this is where IP lives
4.    Transport—this is where TCP lives
5.    Session
6.    Presentation
7.    Application

You’ve heard of an Ethernet cable?  That’s because it’s PHYSICAL.

Ethernet is a Physical layer & MAC standard (The definition actually covers Layers 1 & 2 of the OSI model).  It defines how data “packets” are transmitted on the physical cables.  Ethernet is used for wired interfaces (the most common being the RJ45 cat5 cable, but it covers many copper & fiber-optic cable types).
TCP/IP are higher layer protocols that are mostly in layers 3 & 4 of the transport protocol (IP is layer 3 and TCP is layer 4, see above and the hyperlink).  TCP/IP can be used over many types of network interconnects.  TCP/IP is used on Ethernet links, on WiFi links (WiFi is NOT Ethernet), and even by your cell phone (in fact, if you have a 3G LTE phone, everything is done over IP).

Here’s a bit of how it works:

ARP is a layer 2 protocol that resolves Network addresses (IP) to Data Link addresses (MAC) so the layers can communicate.  Address Resolution Protocol

MAC addresses include Ethernet header information.  Each layer depends on the other layers.  At a high level, from the IP address of your machine over a TCP connection to the Data Link Mac Layer (resolved via ARP) to the wire (Ethernet/Physical), and now you’re communicating via “1s and 0s” (bits/bytes) on the wire.  Just as easy as 2 soup cans connected by a shoelace :).

You’ve heard of IPv4.  Version 4 became the most popular version of IP.  IP adds an IP header. You’ve heard of IP addressing?  

TCP is the connection oriented protocol.  Wikipedia has it right:  Ethernet

Back to the OSI hyperlink example, note how the TCP/IP protocol stack has its own 4 layers. TCP/IP is are both protocols.  Ethernet exists in both the OSI model and the TCP/IP protocol stack.  

Again, each layer is dependent on the others.  For example everything is dependent on the Physical Layer.  Well, wireless (WiFi is not Ethernet), is a different question :).

Here’s a link to more fun mnemonics OSI Reference Model Layer Mnemonics

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Previously published on Quora.

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