Do you have a dumb question that you're kind of embarrassed to ask in the main thread? Is there something you're just not sure about?
This is your opportunity to ask questions. No question too simple or too silly.
Culture war topics are accepted, and proposals for a better intro post are appreciated.
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Notes -
It’s certainly only a model, but answering questions like this is why the OSI model is taught to students: this is the glory of the data link layer! (Or Network Access layer in the more accurate TCP/IP model)
It’s possible, though not really useful, to run a local network over purely MAC addressing, but few pieces of software actually can. But if you’ve ever used wake-on-LAN, digging deeper than IP is how it works!
Every device is intended to have a factory-unique MAC address, though virtual machines, software overrides, and newfangled privacy features just go with the randomize-and-pray model. Since there’s a unique MAC for each device, a host connected to a local network can perform a MAC broadcast without any IP bootstrapping, and hopefully find a DHCP server to hand it IP configuration.
I really love MAC addressing and layer 2 stuff, precisely because this stuff works so transparently in most cases and so you don’t have to think about it. It’s very elegant in that way, and I like elegance and autoconfiguration; it’s the computer’s job to worry about the numbers.
On a tangent: admiration for this elegance was the driving force behind IPv6, and I’d argue the only way to understand IPv6 is to see it’s a design intended to bring the fluidity and elegance of local networks to the internet. This runs into a lot of real-world roadblocks and administrative preferences towards centralized control — yet decentralized but coordinated systems are the great triumph of software engineering and I find it beautiful even if there are real-world obstacles.
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