Vero4k Networking


#1

So I have a question regarding networking on the Vero4k.

As I understand it (could be wrong), the Raspberry pi essentially pipes networking (ethernet prior to RPi3, and ethernet and wireless on RPi3+) through the USB 2 bus, which limits both of those to a max of (100Mbs).

I read that the Vero4k supports wireless AC, and “Fast Ethernet” (is that gigabit?), but still uses a USB2 chipset. Does this mean that the Vero4k networking doesn’t use the USB bus? If not, what is the upper limit for the AC transfer rate? I’m in the process of upgrading my home network to AC4500 which is much faster than gigabit, but if it’s being capped by circuitry at gigabit network speed, I’d rather stick with wired ethernet.

So what’s the max AC transfer speed of the built-in wireless, and why didn’t you go with a USB3 chipset incase we wanted to upgrade to higher transfer-rate devices (sata2usb/networking)? Is it basically that even the fastest 4K video bit rates are still well within the gigabit range?

THANKS!
-Zac


Why 100 not 1000 network
#2

Hello Zac,

Ethernet is connected via an integrated PHY
WiFi is connected via SDIO

So neither depend on the USB bus, and there is no contention here when you are using USB devices such as a hard drive.

The Vero 4K supports up to 433Mbits 802.11ac; however real world performance always guarantees that you will achieve less than this. I get an average of about 200Mbps with iperf, which is sufficient for playing back very demanding content.

We found that Gigabit Ethernet caused some issues, particularly with flow control, which isn’t always handled well with consumer equipment.

There aren’t any ARM based SoCs that support USB 3 at this time.

Cheers,

Sam


#3

Excellent!

OK, so let me restate this to make sure I understand. So “Fast Ethernet” is not gigabit, it’s 100T? Is that a good avg transfer-rate of 100Mbps, or less? The Wireless AC is first-generation-ish so rated 433Mbps but avgs 200Mbps? Either way, sounds like if you have an AC Wireless router you would get better local transfer rates using wireless?

Gotcha. Looks like Marvel and Hisilicon have some new offerings in beta, for the Vero4k 2.0 maybe? :wink:

OH, and don’t forget about maybe a version that enables adding upgrade memory, ala laptop DIMMS. With that, this could be a very powerful little desktop unit as well, but then probably not your focus.


#4



#5

And if memory serves, Ethernet speeds are documented in single vs duplex mode, so practical transfer speeds are 1/2 unless driver supports single/burst mode transfers?

Guessing that’s the same reason the AC433 drops to avg of 200Mbps?

So to rephrase the question, does the avg transfer speed of the ethernet port on the Vero4k suffer the same drop of 1/2? Either way, sounds like AC wireless is the way to go.


#6

If you would have read (at least the first half) of the article I linked you would have seen that Fast Ethernet supports Full-Duplex which should now be supported by all modern hardware so you get 100Mbit


#7

Yes, while switches/hubs operate in full-duplex by default, locally the “mode” is controlled in the device by the driver configuration. So my question still stands, is the driver configuration for the Vero4K full-duplex?

I ask because it’s sort of “a red flag” that the 433Mbps capable AC wireless hardware, is averaging 200Mbps which would appear to be half-duplex?


#8

It’s not that, it’s the fact that 433Mbps may be the link speed, but over WiFi this isn’t realistic.
This is excluding things like TCP overhead.


#9

Sorry, I’m not trying to be difficult, but why is 433Mbps not realistic over WiFi? Especially now that most AC routers are in the 2Gbps+ link speeds. Is the reduction to 200Mbps avg transfer speeds over the Wifi interface because of kernal/driver/software limitation specific to the Vero4k, or some other reason? Just trying to understand…

But again, on wired do you get the full 100Mbps transfer speed, or is there something (besides the TCP overhead) that reduces that number as well?

THANKS!


#10

Relevant google search terms theoretical speed vs real world speed

Yes.


#11

Even with a 2400 link speed, you wouldn’t get 2400Mbps.
There’s a lot of reasons for this however.

100Mbps is fine for even UHD Blu-ray rips, which will account for almost all 4K content, and certainly the highest bitrate 4K content.

Sam


#12

OK, yeah, I get theoretical vs real world, but with say an AC2600 router, would the AC433 of the Vero4k see a better than 200Mbsp transfer speed? In other words, where is the limiting factor? In the network, the device, the interface, the software, etc.?


#13

Maybe a little context here. I’m contemplating putting together a vehicle system for my SUV, for long trips.

Folks would choose their video playlist before we leave. I download all that content, then I fire up a mass transfer of all that data to the vehicle sitting out in my driveway. So, it’s less about the playback bps, than it is about raw transfer speeds of bulk data.

So would it be better to setup a dedicated NAS device in the vehicle with its own high AC link-speed nic, or can I reliably count on the multiple Vero4ks (one for each passenger) to handle their bulk transfers in a timely enough fashion?


#14

Use Ethernet for that if possible

802.11ac would be fine if the base station can handle it.

It would only benefit more devices on the network.


#15

This is a nice article about theoretical vs real-world speeds - and why the marketing department ought to be reined in when it comes to advertised speeds (but isn’t).


#16

OK, things are coming together for me now.

Still unclear on Sam’s last comment though, about ethernet being better for my vehicle scenario.

So in my vehicle scenario, let’s say I had four Vero4Ks in the vehicle, and I a had beefy tri-band AC router with built-in USB 3 NAS, Given that I had pre-downloaded all the content to the NAS, I could then fire-off a script that would push content to each of the Vero4Ks at ~200Mbps each, meaning a cumulative ~600-800Mbps transfer of data, right?

Thanks for the discussion everyone!


#17

No one can give you more than hypothetical answers to your hypothetical questions. The answer is to try it.


#18

Well ~$500 is a bit more than I’m comfortable with as a “try it” scenario, so even hypotheticals from people with more knowledge than me would help in that decision. :smiley:

Even if it’s something as simple as, “the math looks right” (100Mbps vs ~700Mbps}


#19

I doubt if anyone here has any real-world experience of the scenario you envisage. But I can offer some very general advice:

  • wireless is an inherently unpredictable medium that’s prone to outside interference, cable a lot less so;
  • in a car, I’d advise screened cat. 5e cable, since the environment might be noisy;
  • you’re unlikely to need more than 100 Mbits/second to each device, since you’re not feeding a 60 inch TV.
  • you’ll save a lot of money sticking to cable since the router doesn’t need to be bleeding edge. As long as the router’s total simultaneous throughput is more than 400 Mbits/sec across its 4 ports, it’ll probably do just fine.

#21

I don’t mean within the vehicle, I mean from my home router, to the vehicle parked in my driveway. :slight_smile:

Like I said, I’d do the downloads in advance to a NAS, and then when we go on a trip basically do a playlist style file dump to the various Vero4Ks in the vehicle. From there each would just play from its internal memory.