The Internet Still Runs on 40-Year-Old Ideas | Shop Talk EP 91

In Shop Talk #90, Dave and Glen answer a deceptively simple viewer question: when you send something online, how does the Internet find the right computer—possibly on the other side of the world? We follow the journey from Ethernet’s electrical signals and MAC addresses through switches, routers, IP, ports, applications, UDP, TCP, QUIC, DNS, and deterministic network latency. Along the way, Dave tackles duplicate MAC addresses, collision and broadcast domains, synchronization on the wire, VLANs versus subnets, packet captures, traceroute, protocol evolution, and how old standards remain compatible as the Internet changes around them. The conversation also ventures into Windows networking history, including the TCP/IP implementation in Windows NT, routing in NT Server, why TCP/IP wasn’t entirely plug-and-play in Windows 98, and a remarkable early networking war story involving Ethernet checksums, faulty DMA, and a VAX. Later, we revisit forgotten and unusual networks such as Token Ring, FDDI, IPX/SPX, ARCNET, Banyan VINES, and SNA over Ethernet. Finally, the discussion moves into automotive and real-time networking: Tesla Etherloop, AVB and time-sensitive networking, LIN bus, diagnosing vehicle bus errors, classic-car retrofit security, and undocumented Modbus connections in solar systems, transfer switches, and generators. Questions discussed include: • How does a message find a computer on another continent? • What is the difference between collision and broadcast domains? • How do Ethernet endpoints synchronize? • How are voltage levels converted into bits? • What happens when two devices use the same MAC address? • Can manufacturers run out of MAC addresses? • How does an IP packet reach the correct application? • What is the difference between UDP and TCP? • Where does QUIC fit into the network stack? • Can Ethernet latency be deterministic? • How are VLANs different from IP subnets? • How did networking work in early versions of Windows NT? • Why wasn’t TCP/IP completely plug-and-play in Windows 98? • What were Token Ring, FDDI, IPX/SPX, ARCNET, and Banyan VINES? • How does Tesla Etherloop differ from conventional Ethernet? • Could AVB or time-sensitive networking operate over CAN bus? • How do mechanics diagnose bad packets and vehicle bus errors? • What security risks should be considered when modernizing a classic car? • What did Dave remember about Ethernet, and what did he have to research again? Shop Talk is the weekly Q&A show from Dave’s Attic, where Dave Plummer and Glen Hodges discuss viewer questions, engineering stories, retro computing, Windows internals, networking, hardware, cars, software history, and whatever else the comments drag into the shop. 00:00 - Hey I’m Dave… 00:20 - How Does My Message Reach Another Continent? 02:31 - Hubs vs. Switches vs. Routers 03:12 - How Were Network Protocols Designed for the Future? 07:36 - Ethernet Voltage, Encoding & Why CSMA? 08:40 - How Does Ethernet Stay Synchronized? 09:32 - What Happens With Duplicate MAC Addresses? 10:41 - What If a Company Runs Out of MAC Addresses? 12:11 - Moving Up the OSI Model 14:18 - UDP vs. TCP 16:09 - Can Ethernet Latency Be Deterministic? 18:04 - More Network Layers: TCP/IP, UDP & Beyond 18:45 - Wi-Fi: CSMA/CD vs. CSMA/CA 19:15 - Can We Dissect a Packet Capture? 19:59 - VLANs vs. IP Subnets 22:48 - Windows NT 3.1, STREAMS & TCP/IP 25:10 - Could Windows NT Act as a Router? 26:40 - Why Wasn’t TCP/IP Plug-and-Play in Windows 98? 28:08 - TCP Segmentation & Retransmission 30:42 - Token Ring, FDDI & IPX/SPX 32:06 - Ethernet vs. ARCNET, Token Ring & Banyan VINES 32:51 - Ethernet vs. Tesla’s Etherloop 33:22 - AVB, Time-Sensitive Networking & CAN Bus 34:43 - What Is LIN Bus? 35:36 - How Do You Diagnose Bus Errors? 36:01 - Adding Modern Tech to Classic Cars Safely 39:21 - How Much Ethernet Did Dave Actually Remember? 41:20 - Shenanigans and outtakes… 43:59 - The Friendly Coder…