Comment by topspin
6 hours ago
That link notes:
"Card supports 10Gbit/s and 10/100/1000/2500/5000/10000Mbit/s Ethernet"
Nice to see; some NICs are shedding 10/100 support. Apparently, it's not necessary to do this, even in a low cost device.
6 hours ago
That link notes:
"Card supports 10Gbit/s and 10/100/1000/2500/5000/10000Mbit/s Ethernet"
Nice to see; some NICs are shedding 10/100 support. Apparently, it's not necessary to do this, even in a low cost device.
100 mode saved me once when I really really really needed to have a connection in that moment, but the ethernet cable glued to the wall that I was using had only three out of eight wires even functioning.
Don’t we need at least four for 100 Mbps?
According to the technician I spoke with, he could only detect three on their end.
The cable was chewed through by cats, so perhaps it was three just in that moment.
The connection was overall unreliable, so I guess it must have been four, just not all of the time.
There is two wire ethernet that supports 100. It isn't common, but automotive is starting to use it.
Low-cost devices are exactly where 10/100 is still widely used. On PCs, it's a common power-saving mode.
TVs too.
For those of us who don’t know, how does it save power vs a 1gbe running at low throughput?
> how does [100BASE-TX] save power vs [1000BASE-T] running at low throughput?
100BASE-TX uses just two pairs (lanes), one for sending and one for receiving. 1000BASE-T uses all four pairs, for both sending and receiving. Therefore, a 100BASE-TX interface that's only receiving needs to power up one pair. A 1000BASE-T interface needs to power all four pairs all the time.
I recall reading about some extensions that allow switching off some of the pairs some of the time ("Green Ethernet"), but I think that they require support on both sides of the link, and I'm not sure if they are widely deployed.
I assume it is for wake-on-LAN. This of course requires the NIC being powered on while the system is sleeping. Lower bandwidth mode = less power draw.
100 is needed for embedded stuff, it'd render a lot of devices unusable (wiznet chips are popular and are 100 only). That'd suck.
There are plenty of embedded chips which only provide RMII. No RGMII or alternatives.
Lots of industrial sensors and devices only do 4 wire 100BASE-TX so if there's no fallback to that it would be a paperweight in those situations.
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That hasn't been true on switched networks in probably 20 years or so.
Isn’t that only relevant for network topologies that rely heavily on broadcasting to multiple nodes. Eg token ring, WiFi and powerline adapters?
For regular Ethernet, the switch will have a table of which IPs are on which NIC and thus can dynamically send packets at the right transmission protocols supported by those NICs without degrading the service of other NICs.
I’ve seen some vlans hit 1mbit BUM filters, I think we had about 800 users on that one. To saturate a 10m link would require a help of a lot of broadcast traffic.
100m is fine. 10m is fine but I can’t think of anything that negotiates 10m other than maybe WOL (I don’t use it enough to be sure from memory).
If I didn ahve something esoteric it would be on a specialised vlan anyway.
We have switches now, hubs just don't exist anymore. Switches are not affected by some devices having a lower speed.
Is that really true? If so, is there a saner way to handle this than upgrade all the things to 10GBE? Like a POE ethernet condom that interfaces with both network and devices at native max speeds without the core network having to degrade?
> Is that really true?
It's not, cf. sibling posts. The GP probably learned networking in the 80ies~90ies when it was true, but those times are long gone.
(unless you're talking wifi.)
That is complete nonsense and not how switched networks work.