USB to Ethernet - Page 1
Forum section: electronics / projects

author: Hextejas
author_rank: Frequent Contributor
timestamp: September 19, 2022, 12:29:41 pm
content: My new laptop is lacking an Ethernet port but does have 2 USB ports. I have seen USB to Ethernet adapters but I wondered if I was losing speed versus a WiFi network. Has anyone done a study that looks at this ?Thanks

author: pcprogrammer
author_rank: Super Contributor
timestamp: September 19, 2022, 12:36:27 pm
content: With USB3 you can get gigabit speeds on a wired network, as long as your switches and routers can handle that speed. With USB2 it won't do that but 100Mbit will work. So it depends on how fast your laptops wifi in combination with your router is, if it is faster or slower.I myself prefer wired over wireless any day, but that is my preference.Edit: Found this one on amazon. No idea if it is good.https://www.amazon.com/AmazonBasics-1000-Gigabit-Ethernet-Adapter/dp/B00M77HMU0

author: magic
author_rank: Super Contributor
timestamp: September 19, 2022, 01:45:51 pm
content: Ethernet link speed and USB speed are completely orthogonal.Some dongles are capable of gigabit, some are not.Some dongles are capable of USB 3.0, some are not.I own a USB 3.0 gigabit dongle which I used on a USB 2.0 machine and it pushed 30MB/s (bytes, not bits) in one direction on a gigabit link. Unlike Ethernet, USB is half-duplex, so symmetric traffic would only work up to 15MB/s each direction, maybe.I haven't tried it on USB 3.0, but in theory it should be limited by Ethernet only: up to some 110MB/s in each direction, simultaneously.Old 100Mb/s Ethernet gear manages 11MB/s and that's no faster than modern WiFi, so make sure you are running gig-E everywhere.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 19, 2022, 01:52:03 pm
content: Quote from: magic on September 19, 2022, 01:45:51 pm3.0 and newer is full duplex.

author: magic
author_rank: Super Contributor
timestamp: September 19, 2022, 01:59:06 pm
content: Yes, you're right.With 5Gb/s available in each direction there shouldn't really be issues running full-duplex gigabit Ethernet on USB 3.0 at max speed, if the chip in the dongle is up to the task.Generic advice: look for dongles with good reviews

author: Hextejas
author_rank: Frequent Contributor
timestamp: September 19, 2022, 02:17:52 pm
content: The dongle that I found in the drawer is USB 2.0, let me see what the WiFi speed is.

author: ajb
author_rank: Super Contributor
timestamp: September 19, 2022, 04:24:19 pm
content: There are so many variables implicit in the basic question that it's almost impossible to give a blanket answer. "Wifi" encompasses a range of different standards with different performance levels, and real world performance is highly dependent on the access point, number of clients, and even the RF environment. There are fewer variables on the USB/Ethernet side of things, but there's still the question of what interface it has (USB2 or 3, Gig or 100Mb), and on the computer side what the USB port type is, where it is in the device tree (is the port on a root hub, or is it on an auxiliary hub, or an external hub, and what interface speed can it operate at given other connected devices), and what other devices the adapter will have to share throughput with. Then there's the question of whether you'll notice any difference between the two. If you're only really connecting to the internet, then your throughput may be far more limited by the ISP connection or the remote systems you're connected to than the internal network. Speedtest may say one thing, but when you connect to some far away underprovisioned webserver you'll likely get something different.Bottom line: try it and see!

author: ejeffrey
author_rank: Super Contributor
timestamp: September 19, 2022, 05:16:12 pm
content: I've used quite a few USB3 to gigabit and also some 2.5Gb and 5Gb adapters and they mostly work fine. In addition to higher bandwidth USB3 has lower latency and a full duplexed switched topology so it is what I would go with if you have a choice but even usb2 has sub ms latency so as long as you aren't really saturating the bandwidth or sharing the USB port with another high bandwidth device it will probably work fine.

author: David Hess
author_rank: Super Contributor
timestamp: September 19, 2022, 08:08:50 pm
content: I bought aStartech ST3300GU3Bsome time ago to temporarily add a Gigabit Ethernet port to a machine until I could get a network interface card for it and got full line speed out of it without problems. The ASIX AX88179 controller also supports 4K jumbo frames and the Startech ST3300GU3B also acts as a hub, so could be useful for a laptop. The external power supply allows it to supply full power to USB loads although I have not taken advantage of that yet.At the time I also considered 2.5G and 5G USB to Ethernet adapters but I had no other hardware to take advantage of the higher speed, and they were all reported as having problems overheating when used continuously for hours on end, which was my application.

author: Scrts
author_rank: Frequent Contributor
timestamp: September 19, 2022, 09:13:10 pm
content: Quote from: Hextejas on September 19, 2022, 12:29:41 pmIs there USB-C port? If so, get an external "docking station".https://www.amazon.com/Adapter-Charging-Ethernet-Compatible-Thunderbolt/dp/B07TVSLDND

author: magic
author_rank: Super Contributor
timestamp: September 20, 2022, 04:06:06 am
content: That's still a USB dongle, but a bulky one.All the concerns related to USB dongles apply.

author: Berni
author_rank: Super Contributor
timestamp: September 20, 2022, 05:12:13 am
content: Yep as long as it is USB3 it will do full gigabit speed trough a dongle.Tho WiFi is also not to be under estimated these days. Once you get to 5GHz WiFi AC and all that you can get some impressive speeds over it. It does a few 100s of Mbit even trough a wall or two.The one issue with WiFi tends to be packet loss. Since it is wireless it can get interference that garbles a packet here or there, after a bit the network realizes it and resends it. This can make packets arrive a few 100s of miliseconds late. But this is usually only a problem with multiplayer games that require a consistent low ping to avoid lag.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 20, 2022, 10:24:37 pm
content: Quote from: Berni on September 20, 2022, 05:12:13 amCouldn't that be worked around by tunneling UDP packets through a tunnel with FEC? Looks like someone tried to implement it:https://github.com/orzhang/rudp

author: Berni
author_rank: Super Contributor
timestamp: September 21, 2022, 05:34:55 am
content: Quote from: NiHaoMike on September 20, 2022, 10:24:37 pmDon't think that would help much since the WiFi protocol has its own error detection/correction methods inside it. So it already attempts to salvage whatever possible as it is passed between the WiFi radios. If something gets too garbled to recover on the receiving side it requests the packet to be retransmitted. This is completely hidden from any TCP or UDP protocols inside the data. The packet simply arrives a few 100s of milliseconds late.This is not so big of a problem in favorable environments tho. If you live in a rural area with less electronics barfing over the radio channels and have a strong wifi signal it should be very rare for a retransmision to be required. This becomes more of a problem if you live in an apartment block and you have 10 neighbors routers shouting over your radio channel.