Building a 10BASE5 “Thick Ethernet” Network (2012) | Hacker News Reader

Building a 10BASE5 “Thick Ethernet” Network (2012)

tech.mattmillman.com

46 pointscyanoacry42 comments

I am so happy that coax bus based ethernet died. One of the hardest to track bugs for me involved a machine named 'chopper', an SGI box set up to monitor a bunch of other machines. Every now and then chopper would report one of the other machines on the network as down, and send out a page to an operator, which got quite annoying. We tried everything we could think of to trace the fault, replacing all the bits and pieces, including entire servers to figure out what was causing the problem.

Eventually the only thing left that we had not swapped out was a BNC 'T' connector at the back of the MAU of chopper itself, the one that was used to put it on the coax bus.

My buddy Jasper and I both looked at each other at the same moment around 4 am or so, bleary from sleep 'that can't possibly be it', let's swap it out. And sure enough that was it.

Apparently that particular 'T' connector had electrical capabilities unlike any other 'T' connector produced before or after. It managed to filter out 'ping' reply packets from the IP address of the server reported as down...

As someone who does temporary ad-hoc (read event) networking, having a coax standard for high speed, long point to point runs would be awesome - barring that, 100 or 1000baseT 2 port POE repeaters (read hub) would also be a boon - you could get nearly 1000 feet by powering from each end of the span.

Why not fiber? Its fragile, expensive, hard to pull, and not well suited to temporary situations, precut armoured fiber is very expensive - coax is fragile, but cheap and easy to terminate.

If you need to exceed that distance you can set up channel bonding over WiFi using multiple channels simultaneously and directional antennas.

Super-G is one implementation but you can also roll your own and on more channels giving you up to 300 Mbit on fairly long hauls.

http://en.wikipedia.org/wiki/Channel_bonding#Wi-Fi

Asus N56U claims to do this out of the box.

wifi wont usually span the distances I'm talking about, speed is not a huge concern, reliable distance spanning is.

Hm. Ok, I've done long-haul wifi with directional antennas over more than a few Km, but not at those speeds. What distances and speeds do you need?

I need to be able to span 500-1500 feet inside buildings and over complex terrain - a microwave shot is easy to do, but most of the stuff I'm doing is not that simple - worse off, most of the places I do this, have their own wireless networks that we are competing with for spectrum.

Ah, yes, if there are other transmitters nearby or in your target area then that complicates matters considerably, especially if you can't dictate what channels those use.

Another option then might be to have a spool of fiber and to use that instead. Fiber will happily go longer distances without much chance of interference or repeater issues. It's a more expensive option than copper but if you need to go over the easy-to-do-with-copper distance that might be a viable solution. Best of luck with this, it's funny how doing the last kilometer of a link can be harder than getting packets from here the other side of the Atlantic. Very easy to take infrastructure for granted.

You can probably do that with Ethernet extenders, depending on the speed you need. This one does 50 Mbit.

http://www.blackbox.com/Store/Detail.aspx/LinkGain-Ethernet-...

Find the right coax with the right impedance, then stick wifi cards on both ends and connect directly...

This can't possibly... I don't even... wait what?

Not the first time that's been considered. https://electronics.stackexchange.com/questions/103443/close... No follow-up on whether it actually worked though.

You can run antenna's a LONG ways from your wifi card by simply hooking up a VERY long wire. It's the same principle as your satellite dish.

This is also how you do testing of wifi in a way that won't interfere with outside signals.

It's the same principle as the old coax networks.

FYI there are a variety of MoCA products out there that support 175Mbps Ethernet over coax up to 300':

http://www.amazon.com/gp/aw/d/B008EQ4BQG?pc_redir=1414247414...

Thats actually kinda cool!

10BASE-2 was pretty annoying. Nothing was worse than losing your connectivity because someone else unplugged their machine from the string incorrectly.

It's pretty interesting to read into the original "broadcast" ethernet specs.

The "thick yellow wire" and the "coax" both had a single broadcast domain for all devices on the segment. You then linked segments with a bridge (so you could scale networks).

Some things I find interesting about them:

1) The idea is based on radio broadcast (ALOHANET). Since you're using radio broadcast there, a single collision domain makes sense. http://en.wikipedia.org/wiki/ALOHAnet. The protocol is best understood as "room full of people shouting at each other". Don't start talking if something else is, and if two people start at the same time, you both back off. Simple as that.

2) If two nodes try to transmit at the same time, you get a collision and both retry. The spec has a random retransmit timer to avoid immediate (and perpetual) recollision. Requires fair nodes...

3) The max cable length and packet size and related via the speed of light (in copper): http://www.wildpackets.com/resources/compendium/ethernet/pro...

4) It was (semi-)reasonable to use a "vampire tap" connector to dig through the insulation and into the core of a the "thick yellow" copper cable. Just don't wiggle it and cut the copper (or introduce too much of an edge and get signal reflection and hence more collisions).

5) When you had a copper connection between all the ports on your network, an etherkiller really meant something. (A cable, mains plug on one end, coax connecter on the other. Plug in and fry every network card on the segment). RJ-45 etherkillers are single-target. Pah.

Ethernet is still "broadcast" (CSMA/CD). It's just that now, with switched ethernet, the broadcast domain is reduced to the switch port and the station.

One network which I have a particular fondness for is Arcnet. It also used "thick ethernet" (93Ω) cabling, but all stations were connected to a central hub. It was remarkably resilient.

I used it a lot for gaming (LAN parties), back in the days when Ethernet (that's thin coax ethernet) cards were still expensive. Arcnet equipment could be obtained for cheap (or even free), the speeds were enough for gaming (Doom, Quake, Descent), the DOS drivers were great, and overall it was a great solution which Just Worked. Most importantly, it didn't have the problem of one person bringing down the entire network just by disconnecting the cable at his station, which thin ethernet had.

See http://en.wikipedia.org/wiki/ARCNET for more details.

I worked for a systems house in the UK during the 1980s-90s and we were a major UK Olivetti reseller and distributor; Olivetti seemed to have a particular fondness for ARCNET and I was involved in many installations.

One large job I particularly remember was in the admin block of a large seaside holiday and entertainment complex. The block was several floors high and the apex roof was 'U' shaped; when working in the roof space, you could either walk around the 'U' from end-to-end (a total length of about 200m), OR cut across the middle through a pair of external doors and across the central flat roof - but the roof was guarded by some VERY territorial and VERY big seagulls. Using the short cut was a risky business as the gulls would take flight and begin dive-bombing!

Points for mentioning Descent. A decent remake would be excellent... the extra resolution of its successors somehow failed to maintain the grit of the original. We used to play over serial cables before we had ethernet. Incidentally, another favourite at the time was Heretic. For no apparent reason my system used to work much faster at Heretic than anyone else's, showing excellent screen refresh rates despite an equivalent or lower CPU clock. Never quite figured that one out, perhaps the (Oak?) video card, the motherboard, or the RAM clock speed. Ahh, the days before pervasive internet... where social networking meant plugging cables.

Amen, Descent rocked.

Descent came up 4 months ago on HN: https://news.ycombinator.com/item?id=7948262

http://descentchampions.org/new_player.php

Yup. Arcnet is under appreciated. I still have a small setup for an ancient embedded (STD-Bus) setup. Memories...

Cached link - http://webcache.googleusercontent.com/search?q=cache:_rBACik...

"Error establishing a database connection"

10 Mbit/s doesn't cut it apparantly.

How do you know his database server is on the other end of a 10 Mbit link? What if the datbase and the web server are on the same box and the outside link is doing just fine but his db is simply overloaded?

I don't think you can take it as given that the network is the problem when you see an 'error establishing a database connection'. I'd start with looking at the database.

I assumed it was a joke.

woosh. He was clearly joking.

On another note... this is clearly MySQL. I recall this error from the 1990s

Wow, this is a blast from the past, circa 1992-1998. For my sins I used to maintain a fairly large Thick Ethernet network for a large textile manufacturing company in the UK (working for a contractor that basically had very few clues about employee health and safety, hindsight is a wonderful thing).

A fair chunk of this network ran through their factory up in the factory roofspace. I used to climb these ridiculously high step ladders to reach up into the factory roof steelwork to install "vampire taps".

It used to scare the bejesus out of me, mostly due to an aversion to heights, the other being that the factories produced cotton thread, which during one of the processes requires the application of a fine mist of wax or light grease, I don't remember why. But every high up surface was deceivingly lubricated with a fine layer of wax or grease as a result of being kinetically atomised into the air by high speed thread spinners, rollers, spoolers and guides. To further focus your mind, there was also an opportunity of being impaled on these massive crane lifted pointy multi-spool holder things should you put a foot wrong (they were used to lift large bulk spools of rough spun cotton into even larger dying machines).

Although we had a proper coring tool my biggest fear was of creating a short between the shield and core and unf*cking that up a 30 ft step ladder in that environment would have ruined my day (we had to install these things on live segments, there was no downtime permitted). Fortunately the quality and accuracy of the tooling was good, the customer used the correct cable (not some cheap imitation) and my karma and anxiety levels could return to normal once the transceiver lights flickered into life.

Just thought I'd share my lasting memory and experience of 10BASE5 hands on work.

The most amazing thing here is the USB-to-AUI converter. Wish I could reach the cached page for that.

here you go.

http://tech.mattmillman.com/wp-content/files/axaui_m1.pdf

http://webcache.googleusercontent.com/search?q=cache:_rBACik...

He doubts network gaming would have taken off?!

I spent many hours playing Doom and Warcraft 2 on exactly this setup! (Feeling a bit old now...)

Wow. I admire this amount of attention to detail (with the custom USB to AUI interface) for a ”fun” project. Nice work.

I hope he enjoys going round and working out which ethernet connector has fallen out, because of those useless "slide locks". I definitely don't miss thick ethernet.

I actually have a couple of old PCI ethernet cards that have both standard RJ45 connectors and BNC coax connectors. Does that mean I actually have something rare?

Probably not. I had a whole drawer of them up until a couple of years ago. I chucked most of them (possibly with the exception of one, "just in case"). You'll probably find hundreds of them piled up in the "spares" rooms of loads of IT departments.

Not as rare as the handful of PCI ethernet cards I have with a RJ45 and a DB9 connector. 100BASE-CX, ethernet over STP, used for a very brief period of time so people could reuse their Token Ring wiring plant for Ethernet.

Is it DB9, or AUI? (AUI is 15-pin, and is the card required for this story)

DB9. As I said, it's so customers with a wiring plant based on Token Ring STP (aka Type 1) could use ethernet at the end points without running new wiring.

As I understand it the BNC connector is not rare, it's the AUI connector that's hard to find.

That's the 15-pin VGA-ish connector in the card pictured.

I remember when I first mount a network on my house to play with my brother DooM , with coax Ethernet and with a few ISA network cards that I got for free...

next you have to try the old standard of terminating either or both ends of your thick ether with thin ether (and then real terminators at the far ends of that)

(and yes thick ether standardly came with connectors on the end, I still have a roll somewhere, I have no idea why)

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