The physical layer includes the physical mediums such as fiber optics, coaxial, and twisted pair cables. For network engineers, we're typically working from the physical to the transport layer. For us we typically refer to the bottom as number one and gradually increase up to layer seven. From the bottom up their physical, data link, network, transport, session, presentation, and application. It breaks the technologies into seven layers each built on top of each other. According to Wikipedia the OSI model is a conceptual model that categorizes and standardizes the communication functions of a telecommunication or a computing system without regards to his underlying structure and technology.

When we talk about IP addresses and routings later in this course, they're generally residing at layer three. The network layer governs the structure and transfer units of packets. The data link layer handles the data frames between two nodes.

The MAC address is a unique identifier assigned to a network interface CAD to uniquely identify the narrower interface it is assigned to. MAC stands for media access control. I would encourage you to take a look at the Wikipedia patient OSI model, if you're interested in learning more about it. Of course, this is the overgeneralization of the OSI model.

Because of its uniquely identifiable address and they're not easily changed, the MAC address has many other names. So on a computer with Ethernet, Wi-Fi, and Bluetooth interfaces, each of them should have a uniquely identifiable MAC address. Each of the interface should have a MAC address to uniquely identify yourself. It is a number of purchase from IEEE registration authority. The first 24 bit of the MAC address consists of the OUI or organizationally unique identifier. Each group consists of two hexadecimal units.

Referring to the OSI model, this is a layer two level. The dominant technology in LAN today is Ethernet. These nodes could be laptops, computers, smartphones, or printers. A local area network is typically a single network where the nodes could reach each other. In modern local area networks We usually have a bus topology where the nodes are connected physically to the wire with each other.

In our example, if A once your transmit data frame intended for B the hub was still transmit the data frames to B and C. With a hub traffic coming in from any port is replicated by the hub and transmit it to all the other ports. In the early days, we typically used a device called a hub to connect these nodes. In order for the nodes on the land to reach each other the data needs to be transmitted from the source to the destination.

For example, it offers better security. There are many advantages of partitioning the network into different VLANs. The ports that is connected to the hosts are called access boards and the ports connected to switches togethers are called the trunk ports. We can also chain the switches together so the VLAN information could be extended over multiple switches. The switch would have a MAC address table for each and contain only the MAC addresses for the devices in that VLAN.

There are many advantages to having VLANs in our network. By reducing the traffic we can increase the performance of our network. By partitioning our network into separate VLANs we could reduce the amount of broadcast traffic overall and reduce their traffic and processing resources.

Mac Address Stands For