3 ms·

> In those days we also still used 10base2 so there wasn't even a switch involved You’re thinking of a hub (repeats all packets on all ports). This is how I r

> In those days we also still used 10base2 so there wasn't even a switch involved You’re thinking of a hub (repeats all packets on all ports). This is how I recorded Vonage VoIP calls 20 years ago from anyone using the same hub in the residence.

dgl 3y ago
10baseT would imply a hub, but 10base2 is “thinnet” (because the cable was thinner than the previous standard) where a coax cable runs between all devices on the segment, with no central device connecting them together. https://en.wikipedia.org/wiki/10BASE2 https://en.wikipedia.org/wiki/10BASE2
- shagie 3y ago
  Incidentally, it was the same signal that ran on 10base5 with the vampire taps. At the lab I hung out in as an undergrad, someone found what was termed "the connector of evil." On one end it looked like a thinnet terminator and on the other it looked to be a thicknet terminator - but they didn't terminate, it was a pass through. And we used it. Some of the machines had 10b5 connectors and some had 10b2. The ones that used 10bT were at the other end of the room where the hub was. The fun part was tracking down the inevitable "that machine dropped off the net" because the standing wave wasn't quite right for the thicknet side (and made the thinnet side unhappy too). So we set it up to do a ping -f of an IP on the subnet that was on the 10bT side and redirect it to /dev/audio. This way machines that were on the net had speakers that were chipping away while those that had fallen off were silent. And then we'd go about swapping lengths of coax to get the standing wave to establish again when everything was chirping away... until we had to add another machine.
  - genewitch 3y ago
    in the mid-90s i was invited to fix several schools' networks, a couple were novell and i forget what the others were (edit: also appletalk, which was similar but used 2 pairs on "telephone jacks", including little phone jack resistors), and those BNC connectors (or were they TNC?) were connected to stiff wires so any movement of the very heavy PCs connected to them tended to shear solder joints. I even had to replace "thinnet" coax that rats had eaten through. I bet if i open my parts cabinet i still have enough stuff to build a token ring 10base2 network right now.
- NoZebra120vClip 3y ago
  There existed 10Base2 hubs (repeaters), because there were still limitations on cable length and the need to isolate bad segments.
wkat4242 3y ago
No. Not a hub. That was 10baseT. 10base2 was a coaxial cable (RG-58) shared by all devices. Each would have a T-splitter and there would be a terminator plug at the end. Removing that would cause half the network to stop working. Before that there was also another standard with ticker cable (RG-213) called 10Base5 but that was before my time. 10Base2 was still the way the network worked everywhere in my college though. It was expensive and messy. Technically it worked a bit like a hub but it was a very different topology. At least physically (electrically it wasn't too different from how a hub shares its signals)
- chasil 3y ago
  The hub was built to emulate the behavior of 10base2 and 10base5. 10base5 was the original inch-thick coax, and adaptors actually drilled into the cable. I have found 10base5 taps in odd places over the decades of my career. 10base2 was coax cable that we recognize, and there were t-connectors that allowed two cables to link into a host's network adapter. The ends of the cable were capped with resistors ("terminators") that would radiate network traffic into (a very small amount of) heat. This model uses CSMA/CD (carrier sense mutiple access/collision detect) very literally. Any station could transmit at any time, up to a maximum of 1518 bytes, including the Ethernet frame header. Transmit collisions were detected as frame size overruns. If the cable were too long, the ends would see correct transmissions, but the middle would see collisions. This explains the 500 and 200 meter limits of 10base5 and 10base2. An understanding of this original topology and its limits is informative in the reasoning for modern Ethernet.

dgl 3y ago

10baseT would imply a hub, but 10base2 is “thinnet” (because the cable was thinner than the previous standard) where a coax cable runs between all devices on the segment, with no central device connecting them together. https://en.wikipedia.org/wiki/10BASE2 https://en.wikipedia.org/wiki/10BASE2

shagie 3y ago
Incidentally, it was the same signal that ran on 10base5 with the vampire taps. At the lab I hung out in as an undergrad, someone found what was termed "the connector of evil." On one end it looked like a thinnet terminator and on the other it looked to be a thicknet terminator - but they didn't terminate, it was a pass through. And we used it. Some of the machines had 10b5 connectors and some had 10b2. The ones that used 10bT were at the other end of the room where the hub was. The fun part was tracking down the inevitable "that machine dropped off the net" because the standing wave wasn't quite right for the thicknet side (and made the thinnet side unhappy too). So we set it up to do a ping -f of an IP on the subnet that was on the 10bT side and redirect it to /dev/audio. This way machines that were on the net had speakers that were chipping away while those that had fallen off were silent. And then we'd go about swapping lengths of coax to get the standing wave to establish again when everything was chirping away... until we had to add another machine.
- genewitch 3y ago
  in the mid-90s i was invited to fix several schools' networks, a couple were novell and i forget what the others were (edit: also appletalk, which was similar but used 2 pairs on "telephone jacks", including little phone jack resistors), and those BNC connectors (or were they TNC?) were connected to stiff wires so any movement of the very heavy PCs connected to them tended to shear solder joints. I even had to replace "thinnet" coax that rats had eaten through. I bet if i open my parts cabinet i still have enough stuff to build a token ring 10base2 network right now.
NoZebra120vClip 3y ago
There existed 10Base2 hubs (repeaters), because there were still limitations on cable length and the need to isolate bad segments.

wkat4242 3y ago

No. Not a hub. That was 10baseT. 10base2 was a coaxial cable (RG-58) shared by all devices. Each would have a T-splitter and there would be a terminator plug at the end. Removing that would cause half the network to stop working. Before that there was also another standard with ticker cable (RG-213) called 10Base5 but that was before my time. 10Base2 was still the way the network worked everywhere in my college though. It was expensive and messy. Technically it worked a bit like a hub but it was a very different topology. At least physically (electrically it wasn't too different from how a hub shares its signals)

chasil 3y ago
The hub was built to emulate the behavior of 10base2 and 10base5. 10base5 was the original inch-thick coax, and adaptors actually drilled into the cable. I have found 10base5 taps in odd places over the decades of my career. 10base2 was coax cable that we recognize, and there were t-connectors that allowed two cables to link into a host's network adapter. The ends of the cable were capped with resistors ("terminators") that would radiate network traffic into (a very small amount of) heat. This model uses CSMA/CD (carrier sense mutiple access/collision detect) very literally. Any station could transmit at any time, up to a maximum of 1518 bytes, including the Ethernet frame header. Transmit collisions were detected as frame size overruns. If the cable were too long, the ends would see correct transmissions, but the middle would see collisions. This explains the 500 and 200 meter limits of 10base5 and 10base2. An understanding of this original topology and its limits is informative in the reasoning for modern Ethernet.