In ethernet, Virtual LAN (VLAN) is an important technology implemented here. Ethernet follows IEEE 802 and allows for variable sized data, while protocols like ATM (Asynchronous Transfer Mode) have fixed 53 bytes of data that it calls 'cells.' It is important to understand that each protocol implements its lower layers differently. Those are Medium Access Control (MAC) and Logical Link Control (LLC). Two sublayers exist here, which is where the confusion can set in. These nodes are usually directly connected, whether that's via LAN, WAN or MAN.

Most people understand that MAC addresses exist at Layer 2, but other than that, why does this layer exist? This layer is primarily involved in transmitting data from one specific node to another. Layer 2 is where many students get hung up when learning networking basics. In the OSI model, swap out power with data. For the most part you simply plug your appliance into the outlet and power is delivered. The physical transmission aspects of Wi-Fi, Bluetooth, Microwave, and other over the air technologies fall under this layer.Īn easy-to-understand non-network example of this is electricity. This is not only limited to physical cables though. The type of equipment involved in Layer 1 uses little to no logic when operating: copper ethernet cables, fiber optic cables, and ethernet hubs. This is the network layer where that happens so that it can be transmitted somewhere else. The argument could be made that all computer data is stored in bits and, ultimately, it is. We will talk more later about its presence and operation in Layer 2.ĭata at this layer is simply bits sent across a wire, many many zeros and ones. In Layer 1, it utilizes physical cabling and radio frequency standards along with the conversion of data to bits. Some protocols operate in multiple layers. Wiring standards play an important role in this layer such as T568A and B for Ethernet, or which radio frequencies to use for Wi-Fi. It covers the physical aspects of networking, and is the lowest and most physical 'rocks and blocks' layer of the model. Let's take a brief look at Layers 1 through 3 of the OSI model - and how they work with different elements of networks. It is easiest to understand them in terms of how each specific protocol has implemented them. Layers 1 through 3 specifically are pivotal but often ignored they can be convoluted.Īn important thing to understand is that each protocol implements these layers in nuanced ways. When studying for network certification exams such as CompTIA Network+, a deep understanding of all of the OSI layers is crucial to your success.

Wifi vs bluetooth osi model