When I was struggling to figure out why so many of my devices on my gigabit network were only getting 100 megabits, I learned that a lot more of my devices were on 10/100 ethernet than I expected. Including some recent purchases (TV's especially).
It took me a while because I assumed gigabit had been kind for far longer than it actually was in practice.
TV stuff doesn't tend to need more than 100Mbps, unless you're playing blu-ray 4k discs which have higher peak rates. Saving a buck or two on the SoC adds up for the manufacturer.
Exactly. You spend $3000 on a TV and now you have a crap experience playing BluRay because the manufacturer saved 12 cents on a Gigabit chip. Good way to lose customers.
It is so frustrating that this can bring down the rest of the network to the lowest common denominator. I know it is the fault of a cheap switch, not the TV, but still.
> It is so frustrating that this can bring down the rest of the network to the lowest common denominator.
It shouldn't? I have 10M to 10G in the same ethernet collision domain everything works at appropriate speeds (my 10G hosts don't always hit 10G cause some of them have anemic cpus, but that's a different story). Most of my switches are cheap gigE switches, not the 10G stuff obviously, so cheap isn't the problem.
Only thing is if some equipment thought ethernet pause frames were a good idea... Send too much traffic to a low speed switch port and get a pause frame will tend to stop all outbound traffic which is not helpful. Not a lot of things send or respect pause frames though...
Pause frames are wild. I have a cheap Legion Go dock and if I leave it with power/Ethernet connected and no legion in the dock, it brings down my whole network after about 30min or so.
Buffer exhaustion can cause it to happen pretty quickly with some normal, non-contrived usage patterns. A 10G host sending large data to a 100M peer will cause all packets between all other peers to drop once switch memory is filled up. Ideally the switch is smarter about this, but cheap switches in the real world…
Imagine 5 devices that all push at 100mbit in 100 milliseconds (1gig linerate) to the target 1gig connected device, then nothing for 900ms.
On paper they are feeding 100mbit a second each to a target receiving 500mbit a second. Easily fits in a 1gig link.
But because of the timing you've got to transmit 500mbit in 100ms, or a peak speed of 5gbit.
So instead you have to buffer and delay the packets. Your near-zero latency increases to 400ms, and your switch needs about 400mbit (50MB) of buffer, or over 30,000 packets of buffer space.
You'd need a very high end switch to avoid any drops in that situation.
I’m not an expert on switching algorithms, but there are various algos they can use for dropping or rejecting packets, or QoS prioritization that are supposed to self limit even a poorly implemented network protocol and provide fair service and reasonable latency even in such a situation.
Again, a cheapo non reputable switch probably runs with whatever settings got it working the first time with no follow up testing. Networking algorithms are an area where the simple dumb thing mostly works except in edge cases and adversarial situations, and the right/proper way to do things is fiendishly complex.
This is generally not related to the switch at all. It's upstream egress to the Internet and the most common cause is buffer bloat. Traffic on a 10Gb link between local hosts won't be impacted by a 100Mb connection going out to the Internet and also a 10Gb connection sending to a 100Mb connection won't either. TCP congestion control matches the speed of the sender and during an initial connection burst the switch will likely buffer for a short period of time (which is exactly why the buffer exists) and drains at line rate. This is normal and all during this TCP is signaling congestion / back off. However, if your egress router doesn't handle buffer bloat you can end up with poor connections leaving the network, but generally this isn't because of local Ethernet speed mismatch or related to the switch at all.
And even in cheap switches (think Realtek / Broadcom chips in $30 switches) they have dynamic shared pools. An elephant flow can exhaust some of that pool, but even the cheap stuff won't allow a single port to exhaust all resources as claimed.
10Gb to 100Gb UDP? Sure... Maybe in this scenario you end up with some odd behavior, but this isn't going to be normal usage. We've got PAUSE frames, congestion control and hardware that's been doing this for decades. Even on the cheap switching. It is imperative to have a router, however that actually deals with buffer bloat appropriately and as your Internet pipe scales you want to be cognizant your router can handle queuing appropriately at those line rates.
But ultimately...
> A 10G host sending large data to a 100M peer will cause all packets between all other peers to drop once switch memory is filled up.
And hubs like that wouldn't work with 1G anyway. (Apparently theoretically some versions of gigabit ethernet could work with hubs but it's not clear any were ever made)
Even UHD Blu-Ray isn't likely to need sustained transfer rates over 100 Mbps. The spec allows transfer rates of about 128 Mbps, and some discs reportedly have momentary spikes above that, but I suspect the vast majority of titles would be playable over Fast Ethernet, especially if given a few seconds of buffer.
This is the biggest problem with those cheap network interfaces in tvs. They dont have any form of usable buffer, so a spike instantly creates problems.
using an usb network dongle (or if your setup is good enough wifi, but this is very unstable)
Also, most tv's are not able to push the full 100Mbps over their network interface.
Will TVs stream UHD Blu-Ray rips off the network anyway? I guess modern TVs all have H.265 decoders now, so there’s no reason they couldn’t as long as the network interface is quick enough and they know how to handle common video containers.
TVs will stream some. Exactly because the network cards are horrible without buffers etc.
But yeah, remuxes (uncompressed copies of UHD) are pretty common and people that want the best quality use them.
Also, kaleidescape highest quality options are as big or bigger than UHD rips.
Totally. It's only inconvenient for a total rounding error of a customer who's trying to stream games from cloud or sunshine/moonlight, where it can cost up to 4ms of latency for higher bitrates.
Yes - I think in cases where you have a good wireless setup at home it's actually preferable to not hardwire the TV. It's easy to get better performance over wifi when the port is only 100mbps.
It took me a while because I assumed gigabit had been kind for far longer than it actually was in practice.