How did Ethernet go from fat cables and vampire taps to RJ35? Is it still exactly the same protocol (is that even the right word?) as it was back then?
I really need to dive deeper into networking…
I really need to dive deeper into networking…
Layers. The physical signaling is vastly different but the content that rides on it can remain the same. If you study the OSI model (https://en.wikipedia.org/wiki/OSI_model) you will know more about it than me.
I don't know how faithfully modern (or ancient) Ethernet follows this model - it might predate this work. Some layers might be blended for the sake of efficiency, but there are definitely layers.
L2 switching also requires the Spanning Tree Protocol, which is definitely not a well-liked part of the stack.
More recently, we also run ethernet over optical fibers. The varience within the fiber family of cables is probably greater than the variance in either copper or coax.
Ethernet has also been run over power cables.
100base-tx increased the symbol rate, added speed and duplex negotiation (layered into the existing link pulse signaling), but otherwise kept things the same; you can even run a 100base-tx hub.
1000Base-T is a wide departure at the signalling level; all 4 pairs are used simultaneously, bidirectionally, the symbol rate is the same as 100base-tx, but each symbol carries more bits. But the ethernet frames are pretty much the same. (Larger frames started appearing around the same time as gigE, as I recall, but that might not be accurate)
At least, at university: students like me that got hired cheaply and rewired everything. :)
That was not a fun summer, but I learned a lot.
> Is it still exactly the same protocol (is that even the right word?) as it was back then?
I would be surprised, given that coax is equivalent to 3 conductors, and catX cables have 8. And that's before we get into fibre. I would expect they have sime high-level protocol (frames etc.) that gets mapped onto the physical signaling, but I don't know much about that (resource suggestions welcome!).
I do know that going from a broadcast medium to switched point-to-point is a lot more efficient etc.
Plus the taps were notoriously unreliable (variable connection quality). And would cause reflections in the cable as well, which is fun.
The cables form the physical connection, on that Ethernet defines a way to determine who may send a message (essentially anybody can send while quiet, and if a conflict is detected everybody retries after a random time)
The big thing which changed is that we are often using switched networks, instead of all nodes attaching to the same cable, but that's a change in a higher layer.
Ethernet Designers where smart not tontine the spec to properties of a specific material for transport, but abstract ether where signals travel.
Trouble is, the femtocell wanted a network connection, and our RF chamber didn't have an RJ45 passthrough. Some emails got sent, the chamber vendor could sell us a new passthrough module but it was on backorder, ETA two months or something.
So the following evening, I swung by the e-waste recycler where I used to volunteer years prior, which meant I could just give the proprietor a wave and then let myself into the back room and pick the pile. And sure enough, I found a couple of 8-port 10base-T ethernet hubs, with 10base-2 connections on the back for connection to a coax segment. I talked him up to twenty bucks so I'd have an expense to submit; the company did not deserve to get this for free.
Back in the RF lab the following day, it was a trivial matter to convert the BNC connector on the hubs to the N connector in the chamber wall, locate one of the hubs inside the chamber, and connect the femtocell to it. The one outside got the internet connection, which had been running at gigabit speeds but now found itself negotiating at 10/half! (I wonder if the campus networking folks get alerts when that happens. Because it's almost surely not what's intended, unless I'm around.)
The younger techs in the lab mere MYSTIFIED at this exotic hardware that could send Ethernet signals over coaxial cable! That must be expensive! How did you come up with it so fast! Whoever made that must've had this application in mind, but what a niche application! Amazing!