Speaker 1: You know, when we sit at a desk and just
Speaker 1: drag a file from our screen to a coworker's folder,
Speaker 1: there's this, I don't know, this expectation of magic.
Speaker 2: Oh totally. It's like teleportation, right.
Speaker 1: You drag, you drop, and poof, the file is just there.
Speaker 2: Yeah. It feels completely instantaneous and clean and totally invisible.
Speaker 2: We just take for granted, you know, we expect the
Speaker 2: technology to just work without ever really thinking about the
Speaker 2: crazy mechanics underneath the keyboard exactly.
Speaker 1: But then you actually look at the physical reality of
Speaker 1: a network and that whole teleportation illusion just shatters completely.
Speaker 1: It really does, because what we're actually looking at is
Speaker 1: this wild landscape of electrical pulses and hexodecimal codes. It's
Speaker 1: this highly choreographed system of invisible traffic that is honestly
Speaker 1: just mind boggling when you dig into it.
Speaker 2: I like to call it the absolute definition of structured chaos.
Speaker 1: Which is exactly why today's deep dive is going to
Speaker 1: demystify that chaos. We are taking you on a journey
Speaker 1: down the invisible hyperfast high way that connects our computers.
Speaker 2: And we're using Mike Meyer's Comtia network plus Certification Guide
Speaker 2: as our map for this one.
Speaker 1: Right, the mission here is to figure out how data
Speaker 1: actually travels. So let's look at a scenario the source
Speaker 1: sets up. Imagine two co workers, Janelle and Dana. Okay,
Speaker 1: they work in administration at this fictional company called mhtechad
Speaker 1: and Janelle has just finished writing a massive new employee
Speaker 1: handbook in Microsoft Word and she wants Dana to check
Speaker 1: it for accuracy.
Speaker 2: A classic office setup, I mean, Janelle needs to get
Speaker 2: a really large digital file to another person in the
Speaker 2: exact same building.
Speaker 1: Now, Janelle could just save that document to a flash drive,
Speaker 1: stand up, and physically walk it over to Dana's desk.
Speaker 2: The old school sneakernet.
Speaker 1: Mess is sneakernet, right, which technically works, but it kind
Speaker 1: of defeats the entire purpose of having computers wired together
Speaker 1: in a modern office.
Speaker 2: Right. Yeah, absolutely, it's terribly inefficient.
Speaker 1: So instead, without Eve turning around in her chair, she
Speaker 1: drags the file across her screen and sends it over
Speaker 1: the network. But and this is the big question, how
Speaker 1: does that file actually travel from Janelle's desk to Dana's
Speaker 1: desk without magic?
Speaker 2: That is the million dollar question.
Speaker 1: Well, by the end of this deep dive. You will
Speaker 1: never look at a plugged in computer the exact same way.
Speaker 2: Again, I promise you won't, because to understand how Janelle's
Speaker 2: file moves, we can't just stare at the jumble of
Speaker 2: cables under the desk or the software on her monitor.
Speaker 2: We first have to look at the architectural blueprint that
Speaker 2: makes the whole system even possible. The source actually spends
Speaker 2: a lot of time on this concept of a network model.
Speaker 1: Okay, let's unpack this. Yeah, when we hear the word model,
Speaker 1: we usually think of like a plastic model airplane, right,
Speaker 1: like a toy. Yeah, it has the wings, the tail,
Speaker 1: the cockpit, but it intentionally omits the incredibly complex internal
Speaker 1: combustion engine exactly. Or think of a computer model predicting
Speaker 1: the weather. It takes this overwhelmingly chaotic reality global wind patterns,
Speaker 1: ocean temperatures, bemetric pressure, and simplifies it into digestible, predictable parts.
Speaker 2: And a network model does the exact same thing for
Speaker 2: the overwhelming complexity of computer networking. It breaks the entire
Speaker 2: process down into discrete individual steps.
Speaker 1: Which makes it something we can actually wrap our heads.
Speaker 2: Around, exactly. And the gold standard we're looking at today
Speaker 2: is called the OSI seven layer model OSI. Yeah. OSI
Speaker 2: stands for Open Systems Interconnection, and it was created by
Speaker 2: the International Organization for Standardization.
Speaker 1: Which gives us seven specific layers to get from a
Speaker 1: physical cable all the way up to the application you
Speaker 1: are actually clicking on. So, starting from the bottom, layer
Speaker 1: one is the physical layer, then layer two is data link,
Speaker 1: Layer three is network, Layer four's transport, layer five is session,
Speaker 1: layer six is presentation, and layer seven is application.
Speaker 2: That's flot to remember it is.
Speaker 1: But the source gives us a classic technomonic to remember
Speaker 1: it from bottom to top.
Speaker 2: Please do not throw sausage pizza away.
Speaker 1: I love that it sounds silly, but I mean network
Speaker 1: engineers use that inemonic constantly to keep the hierarchy straight.
Speaker 2: The thing that really stood out to me in the
Speaker 2: text is how the OSI model encourages modular design.
Speaker 1: Oh yeah.
Speaker 2: Think of it like an automobile assembly line. The person
Speaker 2: whose job it is to paint the car doesn't care
Speaker 2: about the person putting the doors.
Speaker 1: On, not at all. He just expects the assembly line
Speaker 1: to hand him a car with doors ready to be painted.
Speaker 1: Each layer blindly trusts that the other layers are doing
Speaker 1: their specific job perfectly.
Speaker 2: And that modularity is just vital for troubleshooting. Like if
Speaker 2: a backo outside accidentally cuts the main fiber optic cable
Speaker 2: to the.
Speaker 1: Building, which happens way more often than it should.
Speaker 2: Right. If that happens layer one, the physical layer's broken.
Speaker 2: But the software developers who built Microsoft Word at layer seven,
Speaker 2: they don't have to rewrite their entire application to fix
Speaker 2: the problem.
Speaker 1: Oh wow, yeah, that makes sense.
Speaker 2: Gives way for someone to plug in a new cable
Speaker 2: providing that structure was completely revolutionary. If we look at
Speaker 2: the early days of networking, before models like OSI, one
Speaker 2: manufacturer made absolutely everything.
Speaker 1: You mean, like hardware and software.
Speaker 2: Everything you bought a complete package, hardware, software, cables. All
Speaker 2: of it was proprietary, like a walled garden completely. An
Speaker 2: IBM network worked beautifully, but it only spoke IBM. An
Speaker 2: Apple network only spoke Apple.
Speaker 1: So they couldn't talk to each other.
Speaker 2: It made it incredibly difficult, almost impossible really, for computers
Speaker 2: from different manufacturers to actually talk to each other in
Speaker 2: the same office. The OSI model became the universal translator.
Speaker 2: It allowed developer to focus on just building a great
Speaker 2: network card or just building a great web browser, knowing
Speaker 2: it would interface perfectly with the rest of the stack.
Speaker 1: So let's walk down those stairs and build this blueprint.
Speaker 1: Let's trace Janelle's file starting at the very bottom layer one,
Speaker 1: the physical realm, the foundation, because every blueprint has to
Speaker 1: be built on a tangible foundation. The journey of Janelle's
Speaker 1: file literally starts in the physical world.
Speaker 2: This is the hardware, the cabling, and the central connection box.
Speaker 2: Most modern office networks use a specific type of cable
Speaker 2: called unshielded twisted pair or UTP YOUUGP rate. Inside that
Speaker 2: plastic cable casing are four pairs of tiny copper wires.
Speaker 2: Twist it together in a very specific way to prevent
Speaker 2: electromagnetic interference, and those wires are what actually transmit and
Speaker 2: receive data.
Speaker 1: So all those cables from all the different computers in
Speaker 1: the Mhtech office snake through the drop ceilings, down the walls,
Speaker 1: and eventually plug into a central.
Speaker 2: Box, usually hidden away in some dusty equipment closet somewhere.
Speaker 1: Yeah exactly. But here's the wild part. To me Janelle's
Speaker 1: word document. Once it hits that wire, it's not a
Speaker 1: document anymore. It's a stream of binary ones and zeros
Speaker 1: represented by electrical pulses. If you hooked up a diagnostic
Speaker 1: tool like in a silloscope to that copper wire, you
Speaker 1: wouldn't see text or formatting.
Speaker 2: You wouldn't see the employee handbook right.
Speaker 1: You would just see jagged peaks and valleys of voltage.
Speaker 1: A surge of electricity is a one and the absence
Speaker 1: of a charge zero.
Speaker 2: And because it's pure electricity, Layer one is completely blind.
Speaker 2: It doesn't know if it's transmitting an urgent financial spreadsheet
Speaker 2: or like a video of a cat playing the piano.
Speaker 1: It just doesn't care exactly.
Speaker 2: It just moves the voltage pulses from one computer to
Speaker 2: the central box.
Speaker 1: Historically, that central box was a piece of hardware called
Speaker 1: a hub, and the hub was, to put it nicely,
Speaker 1: a very dumb device, very dumb. It was essentially just
Speaker 1: an electrical reputer.
Speaker 2: Yeah, a hub has a fundamental flaw by modern networking standards,
Speaker 2: When a hub receives an electrical pulse from Janelle's computer,
Speaker 2: it has zero intelligence. It doesn't know who the message
Speaker 2: is for.
Speaker 1: So what does it do.
Speaker 2: It simply makes an exact copy of that pulse and
Speaker 2: blasts it out of every single port, sending it to
Speaker 2: every single computer connected to the office network.
Speaker 1: Wait, hang on, if a hub just blasts every single
Speaker 1: electrical pulse to everyone on the network simultaneously, wouldn't that
Speaker 1: create absolute chaos?
Speaker 2: Total chaos?
Speaker 1: I mean, how does Dana's computer know which pulse is
Speaker 1: her employee handbook? And how do the fifty other computers
Speaker 1: in the office know to ignore it?
Speaker 2: That pushes us directly up to the next level of
Speaker 2: the blueprint. Because the physical layer is essentially screaming the
Speaker 2: message to everyone in the room, the network strictly requires
Speaker 2: a filter at the hardware level to sort out all
Speaker 2: that noise. Okay, And that brings us to layer two,
Speaker 2: the data link layer, and a crucial piece of hardware
Speaker 2: called the NIC.
Speaker 1: The NIC the network interface card. This is the piece
Speaker 1: of hardware that actually plugs into the motherboard of your computer,
Speaker 1: right yep. And it's where that twisted pair network cable connects.
Speaker 1: The NC basically straddles layer one and layer two, and
Speaker 1: it's what gives your computer its unique identity on the network.
Speaker 2: Inside every single NIC, permanently burned into a read only
Speaker 2: memory chip at the factory, is a unique identifier called
Speaker 2: the MC address. MC stands for Media Access Control.
Speaker 1: And this is where the formating gets interesting. The source
Speaker 1: breaks down the anatomy of a MESS address. It's a
Speaker 1: forty eight bit value.
Speaker 2: Sometimes called an EUI forty eight or a messe forty eight.
Speaker 1: Right, and because humans are frankly terrible at reading a
Speaker 1: string of forty eight ones and zeros, it is always
Speaker 1: written in hexadecimal format That means base sixteen.
Speaker 2: Yeah. The math gets a little weird here a little bit.
Speaker 1: Instead of just using zero through nine, it uses the
Speaker 1: numbers zero through nine plus the letters A through F
Speaker 1: to represent values up to fifteen.
Speaker 2: What's fascinating here is how the industry ensures this address
Speaker 2: is globally unique. No two network interface cards in the
Speaker 2: entire world share the same MS address. Never The forty
Speaker 2: eight bits are split in half. The first twenty four
Speaker 2: bits make up the organizationally unique identifier or OUI. The
Speaker 2: Institute of Electrical and Electronics Engineers the IEE assigns this
Speaker 2: specific code to the manufacturer.
Speaker 1: So it's like a brand stamp exactly.
Speaker 2: So Sister gets a specific block of codes, Intel gets
Speaker 2: their own block, Apple gets theirs. It's almost like an
Speaker 2: area code. Then the last twenty four bits are essentially
Speaker 2: the manufacturer's specific serial numb for that exact piece of silicon.
Speaker 1: And you can actually see this physical footprint yourself. If
Speaker 1: you are listening to this and you're sitting at a
Speaker 1: Windows computer, you can open up the command prompt type
Speaker 1: in IP canfig all and look for the line that
Speaker 1: says physical address.
Speaker 2: That is your MC address.
Speaker 1: Yeah, if you're on a Mac, you can open a
Speaker 1: terminal and type if canfig. You'll see a string of
Speaker 1: characters separated by dashes or colons like zero zero four, zero, zero,
Speaker 1: zero five six zero, seventy forty nine. That is your
Speaker 1: device's permanent, burned in fingerprint.
Speaker 2: So, coming back to the chaos of the hub blasting
Speaker 2: data everywhere, the NIC is the solution. Think of the
Speaker 2: NIC is a highly disciplined bouncer at the door of
Speaker 2: your computer.
Speaker 1: Oh, I like that a bouncer.
Speaker 2: Right when the hub blast Janelle's file out as electrical pulses,
Speaker 2: every single NIC on the network receives those pulses. They
Speaker 2: all interpret the ones and zeros, but the immediately check
Speaker 2: the destination MAAC address stamped on the incoming data and
Speaker 2: if it's not for them, if that destination address doesn't
Speaker 2: match their own burned in fingerprint, then drops the message entirely.
Speaker 2: It acts like it never even happened. Only data's NIC
Speaker 2: will see its own MAC address on the incoming data,
Speaker 2: accept it, and pass it up to the computer's memory.
Speaker 1: Okay, so the bouncer checks the ID to let the
Speaker 1: data in. But that means Janelle's massive word document has
Speaker 1: to be packaged in a very specific way so the
Speaker 1: bouncer can quickly read it right exactly, because a raw,
Speaker 1: continuous stream of ones and zeros is pretty much useless
Speaker 1: without some kind of structure.
Speaker 2: Which introduces the concept of a frame. A frame is
Speaker 2: the protocol data unit or PDU for layer two. It
Speaker 2: is basically the digital container for the data.
Speaker 1: Here's where it gets really interesting. The source suggests visualizing
Speaker 1: this frame like one of those pneumatic tube canisters at
Speaker 1: a drive in bank.
Speaker 2: Oh yeah, the plastic tubes.
Speaker 1: Yeah, you put your paper check inside, close the plastic
Speaker 1: tube and it gets sucked up the pipe into the building.
Speaker 1: The text actually jokes about a little guy named nick
Speaker 1: Nick living inside the network card who works at a
Speaker 1: table building these canisters.
Speaker 2: Little guy doing all the hard.
Speaker 1: Work, working overtime. And then which is the frame doesn't
Speaker 1: care if it's carrying dirt or diamonds. It doesn't care
Speaker 1: if it's the employee handbook or just a quick email.
Speaker 1: It just holds the payloads safely.
Speaker 2: And that canniser has a very rigid anatomy. In a
Speaker 2: generic wired network, the frame starts with a header. You
Speaker 2: can think of this as the shipping label.
Speaker 1: Okay.
Speaker 2: This header contains the destination m may address where it's going,
Speaker 2: followed immediately by the source and MAC address. Work came.
Speaker 2: Then there's a tight field that tells the receiving system
Speaker 2: what kind of data is hidden inside. After the header
Speaker 2: comes the payload itself, the actual ones and zeros of
Speaker 2: the word document, and finally the cannister ends with a
Speaker 2: trailer called the FCS or frame check sequence.
Speaker 1: Well, wait a second. If these pneumatic canisters are a
Speaker 1: standardized size to move efficiently through the network, how on
Speaker 1: earth does a massive fifty page employee handbook with graphics
Speaker 1: and formatting fit inside one?
Speaker 2: It doesn't. Oh, and this is where the system has
Speaker 2: to work over time. A standard frame on a wired
Speaker 2: network in general only hold a maximum of fifteen hundred
Speaker 2: bytes of data.
Speaker 1: Fifteen hundred bytes. That's tiny.
Speaker 2: It's an incredibly small amount of information. Yeah, so when
Speaker 2: Janelle hits send on a large word document, her computer's
Speaker 2: operating system has to step in. The software chops that
Speaker 2: massive document into hundreds, maybe thousands, of tiny fifteen hundred
Speaker 2: byte chunks. Wow. It hands those sequential chunks to the NIC,
Speaker 2: and the NIC stuffs each individual piece into its own
Speaker 2: individual frame, its own noumatic canister, and fires them off
Speaker 2: down the wire, one by one.
Speaker 1: And then Dana's computer has to put it all back
Speaker 1: together exactly.
Speaker 2: Dana's computer has to catch all those thousands of cannisters,
Speaker 2: open them up, extract the payloads, and seamlessly reassemble all
Speaker 2: the pieces in the exact right.
Speaker 1: Order, which brings up a terrifying thought. We have thousands
Speaker 1: or even millions of these little fifteen hundred byte canisters
Speaker 1: flying through the copper cables at light speed. What if
Speaker 1: an electrical surge from a nearby power cord flips a
Speaker 1: single one to a zero while it is inside the cable.
Speaker 1: It happens, but a corrupted word document is completely useless.
Speaker 2: Right, which is why quality control is so important. That's
Speaker 2: exactly what the FCS. The frame check sequence at the
Speaker 2: end of the canister is for It verifies the integrity
Speaker 2: of the data using a mathematical algorithm called a cyclic
Speaker 2: redundancy check or.
Speaker 1: CRC CRC okay.
Speaker 2: It is fundamentally a form of binary math division wait division.
Speaker 1: How does doing long division on a file check for corruption.
Speaker 1: That sounds like unnecessary maths, slowing down the transfer.
Speaker 2: It sounds crazy, but think of it with simple numbers.
Speaker 2: Imagine Janelle's data equals the number ten. Her network card
Speaker 2: divides that ten by a specific universally agreed upon key.
Speaker 2: Let's say the key is three.
Speaker 1: Okay, ten divided by three right, ten.
Speaker 2: Divided by three leaves the remainder of one. Janelle's NIC
Speaker 2: takes that remainder, the number one, and stamps it into
Speaker 2: the XCS trailer at the end of the frame before sending.
Speaker 1: It okay, So the remainder travels with the file exactly.
Speaker 2: When Dana is receiving NIC gets the canister, it takes
Speaker 2: the payload and does the exact same division problem using
Speaker 2: the exact same key of three. If Dan also gets
Speaker 2: a remainder of one, the math matches perfectly. The file
Speaker 2: is safe, the file survived the trip intact, and the
Speaker 2: frame is accepted. But if a bit flipped during travel
Speaker 2: and that ten became an eleven.
Speaker 1: Oh, I see where this is going.
Speaker 2: Right, Eleven divided by three leaves the remainder of two.
Speaker 2: Dana's computer sees the remainders two, realizes it doesn't match
Speaker 2: the one stamped on the trailer and immediately knows that
Speaker 2: data was corrupted in transit.
Speaker 1: And what does it do with the cryptid canister? Does
Speaker 1: it try to fix it somehow?
Speaker 2: It drops it instantly? Yeah, the frame is considered garbage
Speaker 2: and thrown away, forcing the upper layers of the network
Speaker 2: to eventually realize a piece is missing and asks Janelle's
Speaker 2: computer to resend that specific fifteen hundred byte chunk.
Speaker 1: It just throws it away. That is ruthless, but I
Speaker 1: guess it has to be to ensure perfect data integrity.
Speaker 1: But hold on, I have another logistical problem here late
Speaker 1: on me. For Janelle's computer to build this canister in
Speaker 1: the first place, it needs to write Dana's specific destination
Speaker 1: NEC address on the header. But how does Janelle's computer
Speaker 1: know DANA'SMEC address. It's not like there's a physical phone
Speaker 1: book of forty eight bit hexadecimal numbers sitting on Janelle's desk.
Speaker 2: That's a great question. It needs that address to function.
Speaker 2: So if Janelle's computer doesn't know DANA'SMEC, it uses a
Speaker 2: very specific mechanism to find out. It sends an investigative
Speaker 2: message called a broadcast.
Speaker 1: Frame broadcast frame.
Speaker 2: Instead of targeting a specific forty eight bit device address,
Speaker 2: it uses the universal MAC address ffffffffffff all F.
Speaker 1: Because it's hexadesimal, F is the highest possible value.
Speaker 2: You got it. That all F address is the universal
Speaker 2: broadcast code. When a network card sees a frame address
Speaker 2: to all FS, the bouncer doesn't drop it. Every single
Speaker 2: computer on the mhtech ed network is forced to accept
Speaker 2: that specific frame, open the canister, and read the payload
Speaker 2: like a company wide memo exactly, and the payload basically
Speaker 2: acts as a megaphone saying, Hey, whoever has the IP
Speaker 2: address for Dana's computer, please reply and tell me your
Speaker 2: physical MAC address.
Speaker 1: And then Dana's computer answers yep.
Speaker 2: Dana's computer sees the request, realizes it's the intended target,
Speaker 2: and sends a direct reply back with their burned in
Speaker 2: MPAC address. Now Janelle's computer caches it in memory and
Speaker 2: can send the thousands of document frames directly.
Speaker 1: But if we combine this with what we learned about
Speaker 1: hubs earlier, hubbs blindly blast every electrical pulse out of
Speaker 1: every port, and now we are adding broadcast frames that
Speaker 1: force every single computer to open and read the message.
Speaker 1: If Mhtech has fifty or one hundred computers all sending
Speaker 1: broadcasts and hubs blasting everything everywhere, that sounds like a
Speaker 1: recipe for a complete network meltdown. The cables would be
Speaker 1: absolutely saturated with noise.
Speaker 2: If we connect this to the bigger picture, you have
Speaker 2: just identified why the networking industry had to evolve.
Speaker 1: Oh good, so they fixed it.
Speaker 2: They had to. Relying on hubbs would completely break a
Speaker 2: large modern network. The sheer volume of traffic, the constant
Speaker 2: copying of frames would overwhelm the physical bandwidth of the cables.
Speaker 2: This is exactly why Layer two hardware advanced. The dumb
Speaker 2: hub was replaced by an intelligent device called a switch.
Speaker 1: The switch, which, if you look at it in the
Speaker 1: equipment closet, looks almost exactly like a hub, doesn't It
Speaker 1: Just a metal box with a bunch of ports for
Speaker 1: cables to plug into.
Speaker 2: Physically similar, but internally, a switch is a massive leap forward,
Speaker 2: a switch actually learns. It learns it contains a memory bank.
Speaker 2: Every time a device sends a frame into the switch,
Speaker 2: the switch looks at the source MK address on a header.
Speaker 2: It notes odd, Janelle's MK address is coming in on
Speaker 2: port two. It writes that down in a dynamic table.
Speaker 2: Oh wow. When Dana replies, it logs Dana's MAA address
Speaker 2: is on port five. It dynamically builds a literal map
Speaker 2: of the office network.
Speaker 1: So it's not guessing anymore exactly.
Speaker 2: The next time Janelle sends a frame destined for Dana's
Speaker 2: MTA address, the switch consoles its internal table. It knows
Speaker 2: Dana's on port five. So instead of blasting the electrical
Speaker 2: pulses out of every single port like a hub, it
Speaker 2: sends the voltage only down the specific cable plugged into port.
Speaker 1: That is so much more efficient.
Speaker 2: It revolutionized network efficiency by turning a noisy room where
Speaker 2: everyone is shouting over each other into a sophisticated system
Speaker 2: of private direct telephone lines.
Speaker 1: That's incredible.
Speaker 2: And if you are listening to this on Wi Fi
Speaker 2: at a busy coffee shop right now, the wireless router
Speaker 2: is acting exactly like a modern switch mapping the mac
Speaker 2: addresses of all the laptops and phones, filtering the traffic
Speaker 2: so your device only receives this audio data and ignores
Speaker 2: everyone else's video streams.
Speaker 1: Okay, let's take a breath. So what does this all mean?
Speaker 1: We started with Janelle dragging and dropping a massive word
Speaker 1: document to data. It feels like simple teleportation magic on
Speaker 1: the screen, but it's not. No. Underneath that illusion, an
Speaker 1: incredibly complex ballet is taking place. In fractions of a millisecond,
Speaker 1: that simple text file is chopped into thousands of fifteen
Speaker 1: hundred byte pieces. Each piece is stuffed into a virtual
Speaker 1: pneumatic canister, stamped with a serial number, stamped with unique
Speaker 1: forty eight bit hexadecimal codes that were liter really burned
Speaker 1: into silicon at a factory. The whole package is converted
Speaker 1: into pure electrical voltage sent across twisted copper wires routed
Speaker 1: by intelligence, which is building dynamic memory maps mathematically verified
Speaker 1: by long division to ensure no bits flipped, and finally
Speaker 1: reassembled by the receiving operating system.
Speaker 2: Exhausting just to say it.
Speaker 1: It really is all of that just so Dana can
Speaker 1: read an employee handbook. It really makes you realize how
Speaker 1: monumental human engineering really is to make all this completely invisible.
Speaker 2: It truly is a marvel of modular design, showing how
Speaker 2: layers of technology can blindly trust each other to perform
Speaker 2: highly specific tasks. But you know, looking at the mechanics
Speaker 2: of this blueprint also leaves us with something deeper to consider.
Speaker 1: What's that?
Speaker 2: Well, this raises an important question. Think about that m
Speaker 2: address we spend so much time examining. We just learned
Speaker 2: that every single network interface card in the world, including
Speaker 2: the one of the smartphone in your pocket, your laptop,
Speaker 2: your smart watch, has a permanently burned in universally unique
Speaker 2: forty eight bit serial numbers or identifying exactly who made
Speaker 2: it and which specific unit it.
Speaker 1: Is, right, the manufacturer's OUI and the device's exact serial number.
Speaker 2: And our devices are constantly sending out frames stamped with
Speaker 2: this permanent digital fingerprint just to function on network. They
Speaker 2: broadcast it to find rouders, they use it as the
Speaker 2: source address to send data. It is a fundamental inescapable
Speaker 2: requirement of layer two networking.
Speaker 1: Yeah, they have to.
Speaker 2: So if our personal devices are silently screaming this permanent
Speaker 2: unique serial number out into the airwaves just to get
Speaker 2: a connection. What does that mean for our privacy as
Speaker 2: we carry these devices through public spaces, coffee shops, airports,
Speaker 2: and across networks we don't even own.
Speaker 1: Wow. From an innocent file transfer in an office to
Speaker 1: a permanent digital footprint tracking our devices, that teleportation magic
Speaker 1: definitely has a physical reality. We all need to be
Speaker 1: a little more aware of something
Speaker 2: To mull over the next time you connect to a network.