Hi, could you please clear my confusion. In this video you used IPs and MAC both. In another video (How switches learn MAC addresses) you used only MAC addresses. Now what is the relation between two videos? Do PCs communicate with each other using both IP and MAC and use ARP ? If yes then what was the purpose of the other video where you only use MAC addresses? Whenever two PCs communicate, very first they use ARP to learn MAC and then they send the frame to other PC using the other video? I am so confused
Sure thing, Process 1, the ARP video. The PC's on the same subnet will learn eachothers MAC's via ARP and build and send the frame on the wire towards the switch. The pc's will store ARP info (IP-to-MAC bindings) in its cache so if the macs are already known then no need to ARP for it. That frame the pc's send have a bunch of fields but the two most important fields are the src and dst mac. Process 2, How switches learn MAc addresses video. The switch gets the frame, learns the src mac and stores that info in its mac address table. And then it looks at the destination mac addresses in the frame. If the switch's mac address table has that destination mac address in it already (lets assume it does) , it forwards it to the associated switchport where that destination mac lives. A regular layer 2 switch techincally doesn't care about the IP addresses of the PC's. It never looks deep enough to see those details. For successful forwarding it doesn't need to. It learns src mac addresses as frames come in, stores them or put's them in its mac address table (address book) and looks at that address book to forward frames to their destination. There are some additional details I left out, but I hope that helps. If it still doesn't make sense please let me know and I'll be happy to help.
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Great explanation sir!
Thanks ! Much appreciated. Next one dropping soon.
Nice video! Where is your video 2 on ARP?
I do owe that video for sure, I'm in the process of moving but it will happen. Thanks for watching !
Hi, could you please clear my confusion. In this video you used IPs and MAC both. In another video (How switches learn MAC addresses) you used only MAC addresses. Now what is the relation between two videos? Do PCs communicate with each other using both IP and MAC and use ARP ? If yes then what was the purpose of the other video where you only use MAC addresses? Whenever two PCs communicate, very first they use ARP to learn MAC and then they send the frame to other PC using the other video? I am so confused
Sure thing, Process 1, the ARP video. The PC's on the same subnet will learn eachothers MAC's via ARP and build and send the frame on the wire towards the switch. The pc's will store ARP info (IP-to-MAC bindings) in its cache so if the macs are already known then no need to ARP for it. That frame the pc's send have a bunch of fields but the two most important fields are the src and dst mac.
Process 2, How switches learn MAc addresses video. The switch gets the frame, learns the src mac and stores that info in its mac address table. And then it looks at the destination mac addresses in the frame. If the switch's mac address table has that destination mac address in it already (lets assume it does) , it forwards it to the associated switchport where that destination mac lives.
A regular layer 2 switch techincally doesn't care about the IP addresses of the PC's. It never looks deep enough to see those details. For successful forwarding it doesn't need to. It learns src mac addresses as frames come in, stores them or put's them in its mac address table (address book) and looks at that address book to forward frames to their destination.
There are some additional details I left out, but I hope that helps. If it still doesn't make sense please let me know and I'll be happy to help.