3 ms·
Some things are the same because they've changed considerably. Ethernet used to be a collision domain on coaxial cable, not a switched full-duplex medium on tw
by msla 3y ago
Some things are the same because they've changed considerably.
Ethernet used to be a collision domain on coaxial cable, not a switched full-duplex medium on twisted pair. It changed piece by piece into something that's conceptually fairly different from what it was, especially when it ceased being a collision domain.
https://en.wikipedia.org/wiki/Collision_domain https://en.wikipedia.org/wiki/Collision_domain
> Early Ethernet variants (10BASE5, 10BASE2) were based on a shared wire and inherently half-duplex, representing a single, potentially large collision domain. Collision domains are also found in an Ethernet hub or repeater environment where each host segment connects to a hub, and all segments represent only one collision domain within one broadcast domain. Collision domains are also found in other shared medium networks, e. g. wireless networks such as Wi-Fi.
> Modern wired networks use a network switch to reduce or eliminate collisions. By connecting each device directly to a port on the switch, either each port on a switch becomes its own collision domain (in the case of half-duplex links), or the possibility of collisions is eliminated entirely in the case of full-duplex links. For Gigabit Ethernet and faster, no hubs or repeaters exist and all devices require full-duplex links.
- throw0101c 3y ago> Ethernet used to be a collision domain on coaxial cable, not a switched full-duplex medium on twisted pair. And it's come back full-circle to (radio) collision domains (à la AlohaNet) with Wifi, which I think the vast majority of people use on a day-to-day basis rather than plugging in.
- 1ncorrect 3y agoThe original Ethernet spec uses CSMA/CD[0] 802.11 uses CSMA/CA[1] [0] https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_with_collision_detection https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_... [1] https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_with_collision_avoidance https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_...
- kloch 3y ago> the vast majority of people use on a day-to-day basis rather than plugging in. For last 100 feet yes, but for the entire rest of the network it's either fiber or copper. Notably, Ethernet framing sometimes with additional encapsulation is used everywhere along the path.
- anonymousiam 3y agoThat may have been true in the past, but recently the same principle (using a hybrid) for simultaneous tx/rx on GBE can be employed on a point-to-point radio channel. https://www.microwaves101.com/encyclopedias/simultaneous-transmit-and-receive-star https://www.microwaves101.com/encyclopedias/simultaneous-tra...
- throw0101c 3y agoAnd in which 802.11 amendment is that in? :)
- anonymousiam 3y agoIt's not a standard, it's a technology. 802.3 defines full-duplex (wired) gigabit Ethernet with each end of the peer-to-peer link both transmitting and receiving at the same time over the same wires. Add a similar hybrid to your WiFi PHY and you're done. It does also require MIMO beam forming to cancel the interference from other users on the same WAP.