MAC Addresses Explained | Cisco CCNA 200-301

Hey what's up guys welcome to CertBros. In this video we're going to be looking at MAC addresses So we're getting closer to the end of our journey through the tcp/ip model In this video we're going to be looking at the data link layer the data link Ethernet standards operate here. It's also responsible for adding another type of address called a MAC address. So what is a MAC address? Well first, MAC stands for Media Access Control. It's a unique identifier that is assigned to a network interface card aka a NIC and this is what a mac address looks like. The first thing to know is that unlike an IP address which can be changed, MAC addresses are described as being physical addresses. Think of them like they're set in stone. Burnt into the NIC by the manufacturer. They are unique and cannot be changed ...well you can spoof a MAC address. The address itself is 48 bits long or 6 bytes. Bits and bytes are binary value.s There are 8 bits in a byte and to remember the difference think off eating binary. You take a bite and you will have a mouthful of bits. Anyway the address has two sections. The first 24 bits, or 3 bytes, is called the organizationally unique identifier or OUI It identifies the vendor. The last 24 bits is a unique value that was assigned by the vendor that makes this address unique There are three types of mac-address. Unicast which means a particular unique MAC address like the one we have here. Multicast which is a MAC address used for an application or protocol. This will be sent to all devices but only those with that application or protocol will listen to it. And we have something called a broadcast address. Now this is sent to all devices within a network and a broadcast address looks like this. It's all F's. So back to our unicast MAC address. It's important to note that there is more than one way to show a MAC address and it changes depending on where you're looking at it. Here are three ways to display the same MAC address The top one is six groups of two digits separated by colons, this is typically how Linux or Apple will display their MAC addresses. The middle one is again six groups of two digits but this time separated by dashes. This is how Microsoft display their MAC addresses. Lastly the bottom displays the address as three groups of four digits this is how Cisco displayed their MAC addresses Although you'll likely see the bottom Cisco format when going through the exam you need to be able to look at all three of these and think that is a MAC address Ok so I know what you're probably thinking, we already have IP addresses so why do we need MAC addresses? Well let's look at an example. We have four computers and a switch. Switches are commonly layer 2 devices. When computers are talking to each other in the local area network or LAN, this is layer 2 communication and layer 2 communicates using MAC addresses But when we leave our network this is where IP addresses are mainly used Routers are layer 3 devices and they mainly focus on IP addresses to get the data to the destination. So in summary you can think about MAC addresses as a local communication and IP addresses as global communication We'll cover this more when we go into more in depth switching and routing topics. Before we finish this video, I will show you how to check your own MAC address at home. On Windows you simply open up a command prompt or PowerShell type ipconfig /all to see your interface settings. Find your interface and Remember you might have more than one if you have a wireless interface and look for something called the physical address If you're using Linux or Apple open up a terminal and type in ifconfig and look for the ether address This video is part of our full CCNA course which can be found in the description. So please feel free to go and check that out. If you like this video don't forget to give it a thumbs up, leave a comment and subscribe. The support from you guys really does help the channel grow. Other than that, I hope this helped and thank you for watching

Channel: CertBros

Views: 62,195

Keywords: mac address, media access control, router, network switch, ethernet, network frame, local network, lan, mac spoofing, mac addresses ex, mac addresses explained, what are mac addresses used for, what are mac address, layer 2 address, ccna 200-301, ccna training, cisco, cisco ccna, cisco networking, computer networking, computer networking course, networking, networking tutorial

Id: N7dM_kD28dM

Length: 5min 31sec (331 seconds)

Published: Tue Aug 04 2020