SerialPort

Early Release! Expanding The Ether: The invention of the DEC LAN Bridge (Patreon)

Published:

2024-08-22 18:22:17

Imported:

2026-06

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Content

We're back with another documentary that's been in the works for months. We've had some ups and downs along the way with interviews being cancelled and other delays, but it's finally ready for a release.

We look at early Ethernet and how one device, the DEC LAN Bridge 100, ended up changing networking and laying the groundwork for Ethernet's future success. This was the world's first bridge, and with that came the invention of store-and-forward switching. It's hard to believe that basically the entire functionality of this massive 21lb device is now in the footprint of a small integrated circuit.

There's also an interesting look into exactly how 10BASE5 was installed back in the day, and we're guided through the tapping and termination process by John Reed. John was kind enough to spend over an hour with us going over how all of this worked. Hope everyone enjoys the video as much as we enjoyed making it, and thanks again for all the continued support!

Files

Previews only

EXPANDING THE ETHER: The invention of the network bridge

We discover where all of our Ethernet switches came from: the groundbreaking DEC LAN Bridge 100. Big thanks to Mitch over at https://www.keyways.com for lending us a working LAN Bridge! Check out their website to see their inventory of over **70,000** devices from DEC and beyond. Want more content like this? Support our mission! Send us a Super Thanks and check out our Patreon + Discord community: https://www.patreon.com/serialport Got some retro gear you want to donate? Get in touch with us at serialport.org. Our second channel: https://www.youtube.com/@theparallelport 00:00 — Intro 00:42 — Beginnings 01:33 — Thicknet 04:48 — Tapping into 10BASE5 07:13 — The limitations 09:24 — The Broadband Project 12:52 — Spanning Tree Protocol 15:22 — Trying out the LAN Bridge 100 18:34 — Looking inside 20:02 — The legacy References: Reed, John. (2024). Interview conducted by Serial Port. Kirby, A. (2024). Email correspondence. Kempf, M. (2024). Email correspondence. Burg, U. V. (2001). The Triumph of Ethernet. Stanford University Press. Perlman, R. (2000). Interconnections, Second Edition.on Wesley Longman, Inc. Perlman, R. (1985). An Algorithm for Distributed Computation of a Spanning Tree in an Extended LAN. SIGCOMM '85: Proceedings of the ninth symposium on Data communications. Perlman, R. (2022). Reddit IAmA. https://www.reddit.com/r/IAmA/comments/xl6cc4/comment/ipiehr2/ Varghese, G. The Story of Bridging. UC San Diego. https://cseweb.ucsd.edu/~varghese/TEACH/cs123/bridging.pdf Digital Technical Journal, Number 3. (1986). Digital Equipment Corporation. Kirby, A. (2024). How Engineers at Digital Equipment Corp. Saved Ethernet. https://spectrum.ieee.org/how-dec-engineers-saved-ethernet Ethernet Design Rules. Boston Technology. http://jkob.fizyka.umk.pl/_downloads/TechBrief1_P1.pdf History of Networking: How Bridging Saved Ethernet. Packet Pushers. https://www.youtube.com/watch?v=U6xbEv9AJ0E Interview with Radia Perlman by Steven Johnson | Hidden Heroes. Netguru. https://www.youtube.com/watch?v=Dn2HRz_rtZI Resources: Dicklyon (1977). CC-BY-SA 4.0. Xerox PARC in 1977.jpg. Xerox PARC Archives. Photo of Xerox Alto computers. Joe Mabel (2014). CC-BY-SA 3.0. DEC VAX 11-780-5 - 01.jpg. Telegram & Gazette (1985). A picture of Digital headquarters in Maynard from 1985. Loz Pycock (2009). CC-BY-SA 3.0. DEC PDP-11 Minicomputer in extended variant (edited).jpg Microsoft Research. Photo of C. Gordon Bell. Internet Hall of Fame 2014: Radia Perlman (2014). CC-BY. Imagining the Digital Future Center. https://www.youtube.com/watch?v=G3zJuMht5Kk Kempf, M. (1986). US Patent 4,597,078. https://patentimages.storage.googleapis.com/f0/2d/88/3f0b8258701fb2/US4597078.pdf