For someone that might purchase a corporate MBA or MBP, is this issue only with USB-C adapters? Or is also with USB-C docking stations that contains ethernet? We use Dell d6000s docking stations that contains ethernet, and then connects to that docking station with USB-C to the laptop. Would this setup also have issues if I get a MBA or MBP?
Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
USB-C Ethernet unreliable
- Thread starter mikeboss
- Start date
- Sort by reaction score
The docking stations with Ethernet feature USB Ethernet adapters internally. So it’s the same issue. Gigabit ports will be unreliable. 2.5G ports will be much better.
As a follow up to my previous post, I have completed my comparison i) Belkin 1 Gbps adapter ii) D-Link DUB E-250 2.5 Gbps adapter iii) Plugable USBCE-25000 2.5 Gbps adapter and iv) UGreen 2502 2.5 Gbps adapter.
As far as the test environment and testing are concerned:
- I have a 1.5 Gbps fibre internet connection which when tested at the modem gave upload / download speeds of 940 Mbps / Mbps 940 when connected with an ethernet cable (and the D-Link adapter) to a 1Gbps port on the modem. The testing speeds are therefore relative to 940 Mbps / 940 Mbps as this was the best / max connected directly to the modem (and represents typical performance).
- I have modem connected to a Luxul Epic 5 1 Gbps router which in turn is connected to a number of Luxul AGS-1024 1 Gbps switches. The testing was limited to a maximum speed of 1Gbps because of the router's and swutches' limitations.
- Testing was conducted using the Okla Speedtest app running on a 2021 M1 Max MacBook Pro and an Apple Studio Display. The testing used the same endpoints, private relay off (i.e., the reason for using the app as private relay severely reduces download speeds), and wifi off. The testing was the best possible though not perfect (i.e., time of day, endpoint consistency, endpoint selection, local network traffic, etc.) though there were some clear trends.
- The testing compared the compared the download speeds and uploads with the ethernet connected i) directly to the MacBook Pro and ii) directly to the ASD and daisy chained to the MBP. The testing was performed for each of the four adapters.
- The testing measured the download / upload speed 15 different times for each adapter. The results were then used to calculate i) the average (faster is better) ii) the max - min (lower / smaller is better) and iii) the standard deviation (lower / smaller is better).
- The test results were the ranked and averaged to determine the best ethernet adapters.
As far as the speed test test results are concerned:
- The raw data (i.e., actual runs) and analysis are attached this posting.
As far as the analysis is concerned, some of the key observations are:
- Belkin Adapter: The reduction in download / upload speeds between connecting the ethernet cable directly to the MacBook versus connecting the ethernet cable to the ASD -> MacBook is real. The speed reduction averaged 295 Mbps / 190 Mbps. No other adapter exhibited a significant reduction in download / upload speeds.
The Belkin adapter was the only adapter that use the Realtek 8153 chip and the com.apple.DriverKit.AppleUserECm drive. The other adapters use the Realtek 8156 chip and the com.apple.driver.usb.cdc.ncm driver (with this also being the driver that the ASD uses!). Whether one or both of these differs explains the speed reduction is for others to answer (i.e., it is beyond my capability).
- D-Link Adapter: This adapter had the fastest download speed regardless of connection, the fastest upload speeds averaged between the connection, and a number of other good test results (i.e., minimal speed loss when concencting through the ASD, small standard deviation, etc.).
This adapter would have been the clear winner as it regularly produced trial run download speeds > 910 Mbps (relative to 940, good job Luxul) save for one very bad run in the 750 Mbps range.
This adapter also feel premium as D-Link added a number of "fine touches"; for example, the adapter is listed as DUB250E rather than teh generic 10/100/1000/2.5. This is a feeling of attention to detail.
This adapter was impossible to find new, no matter where I looked. I picked up a Certified Refurbed unit from D-Link and it looks / seems fine.
- Pluggable Adapter: This adapter performed very closely / similarly to the D-Link adapter especially when one compares the performance when teh ethernet cable is connected to the ASD -> MacBook with the two adapters testing very close to each other.
This adapter also comes with great technical support. This is second pluggable product I have owned and will give a shout out for their tech support; it is US based, knowledgeable and fast. While I did not think I would like the e-mail / forum only communication, it works very well.
-UGreen Adapter: This adapter worked (i.e., there was minimal download speed loss when connected through the ASD, there was almost no upload speed loss when connected through the ASD) , I want to stress this point. The results on average (when looking across all categories / test) were more variable (i.e., higher min / max difference and higher standard deviations) than the D-Link and the Plugable adapter.
Were this the only adapter that I ordered, I would have been thrilled because it solves the speed loss associated with the Belkin adapter.
- Caveat: The testing was limited to the four listed adapters (i.e., there are likely others that are as good and possibly better). The testing was not perfect and could be influenced by the time of day, the endpoint consistency, endpoint selection, local network traffic, etc.
Conclusions
- The D-Link and the Plugable adapter both solve the Belkin speed problem when connected to the ASD with aplomb (i.e., minimal variance when connected through the ASD (as compared to a direct MacBook connection).
- The D-Link and the Plugable when comparing and ranking only the D-Link, Plugable, and UGreen adapters (i.e., Belkin should not be a consideration because of the speed loss when connected through the ASD though it perform extremely well when connected directly to the MacBook) tied based on my ranking system.
- What adapter to keep? I am leaning towards i) keeping the D-Link (and return the other two) or ii) keeping the D-Link for home use, the Plugable for travel and returning the UGreen. What do you think I should do noting other options / suggestions are welcome?
I hope this was helpful and interesting.
I welcome comments from others.
Thank you.
As far as the test environment and testing are concerned:
- I have a 1.5 Gbps fibre internet connection which when tested at the modem gave upload / download speeds of 940 Mbps / Mbps 940 when connected with an ethernet cable (and the D-Link adapter) to a 1Gbps port on the modem. The testing speeds are therefore relative to 940 Mbps / 940 Mbps as this was the best / max connected directly to the modem (and represents typical performance).
- I have modem connected to a Luxul Epic 5 1 Gbps router which in turn is connected to a number of Luxul AGS-1024 1 Gbps switches. The testing was limited to a maximum speed of 1Gbps because of the router's and swutches' limitations.
- Testing was conducted using the Okla Speedtest app running on a 2021 M1 Max MacBook Pro and an Apple Studio Display. The testing used the same endpoints, private relay off (i.e., the reason for using the app as private relay severely reduces download speeds), and wifi off. The testing was the best possible though not perfect (i.e., time of day, endpoint consistency, endpoint selection, local network traffic, etc.) though there were some clear trends.
- The testing compared the compared the download speeds and uploads with the ethernet connected i) directly to the MacBook Pro and ii) directly to the ASD and daisy chained to the MBP. The testing was performed for each of the four adapters.
- The testing measured the download / upload speed 15 different times for each adapter. The results were then used to calculate i) the average (faster is better) ii) the max - min (lower / smaller is better) and iii) the standard deviation (lower / smaller is better).
- The test results were the ranked and averaged to determine the best ethernet adapters.
As far as the speed test test results are concerned:
- The raw data (i.e., actual runs) and analysis are attached this posting.
As far as the analysis is concerned, some of the key observations are:
- Belkin Adapter: The reduction in download / upload speeds between connecting the ethernet cable directly to the MacBook versus connecting the ethernet cable to the ASD -> MacBook is real. The speed reduction averaged 295 Mbps / 190 Mbps. No other adapter exhibited a significant reduction in download / upload speeds.
The Belkin adapter was the only adapter that use the Realtek 8153 chip and the com.apple.DriverKit.AppleUserECm drive. The other adapters use the Realtek 8156 chip and the com.apple.driver.usb.cdc.ncm driver (with this also being the driver that the ASD uses!). Whether one or both of these differs explains the speed reduction is for others to answer (i.e., it is beyond my capability).
- D-Link Adapter: This adapter had the fastest download speed regardless of connection, the fastest upload speeds averaged between the connection, and a number of other good test results (i.e., minimal speed loss when concencting through the ASD, small standard deviation, etc.).
This adapter would have been the clear winner as it regularly produced trial run download speeds > 910 Mbps (relative to 940, good job Luxul) save for one very bad run in the 750 Mbps range.
This adapter also feel premium as D-Link added a number of "fine touches"; for example, the adapter is listed as DUB250E rather than teh generic 10/100/1000/2.5. This is a feeling of attention to detail.
This adapter was impossible to find new, no matter where I looked. I picked up a Certified Refurbed unit from D-Link and it looks / seems fine.
- Pluggable Adapter: This adapter performed very closely / similarly to the D-Link adapter especially when one compares the performance when teh ethernet cable is connected to the ASD -> MacBook with the two adapters testing very close to each other.
This adapter also comes with great technical support. This is second pluggable product I have owned and will give a shout out for their tech support; it is US based, knowledgeable and fast. While I did not think I would like the e-mail / forum only communication, it works very well.
-UGreen Adapter: This adapter worked (i.e., there was minimal download speed loss when connected through the ASD, there was almost no upload speed loss when connected through the ASD) , I want to stress this point. The results on average (when looking across all categories / test) were more variable (i.e., higher min / max difference and higher standard deviations) than the D-Link and the Plugable adapter.
Were this the only adapter that I ordered, I would have been thrilled because it solves the speed loss associated with the Belkin adapter.
- Caveat: The testing was limited to the four listed adapters (i.e., there are likely others that are as good and possibly better). The testing was not perfect and could be influenced by the time of day, the endpoint consistency, endpoint selection, local network traffic, etc.
Conclusions
- The D-Link and the Plugable adapter both solve the Belkin speed problem when connected to the ASD with aplomb (i.e., minimal variance when connected through the ASD (as compared to a direct MacBook connection).
- The D-Link and the Plugable when comparing and ranking only the D-Link, Plugable, and UGreen adapters (i.e., Belkin should not be a consideration because of the speed loss when connected through the ASD though it perform extremely well when connected directly to the MacBook) tied based on my ranking system.
- What adapter to keep? I am leaning towards i) keeping the D-Link (and return the other two) or ii) keeping the D-Link for home use, the Plugable for travel and returning the UGreen. What do you think I should do noting other options / suggestions are welcome?
***
I hope this was helpful and interesting.
I welcome comments from others.
Thank you.
Last edited:
Thanks very much. Do you also see the numerous netstat output errors with the NCM driver, as reported in my last post, with your two 8156 based adapters? Do you notice any packet loss? I‘m torn between a rock and a hard place: The 8156 adapters are more efficient, but the 8153’s don‘t report any errors.
I am opting to stick with the 8156 based adapters as they provide the speed that I am looking forward and, while not measured, I have never / not yet noticed any missing or lost information.
In addition, I did not observe / test for that but would be please to do so should you wish.
Would you be so kind to test the terminal command "netstat -di -I enX" (use the numbered interface corresponding to your USB-C-Ethernet adapter) and report the number of "output errors" after some time of usage?
I would be happy to but want to make sure I do it correctly.
Is my understanding correct that based on the below image teh command should be netstat -di -I en4
Please correct / confirm my understanding at which point I will run the command and report back.
Thank you.
It reports, like on my M3 MBA, apparently lots of "Oerrs" (output errors) and some dropped frames. Using 8153-based adapters or the official Apple Thunderbolt Gigabit Ethernet adapter, there usually are zero "Oerrs".
@learjet I appreciate your explanation, it is helpful to me.
I will keep the Apple Thunderbolt Gigabit adapter just inc case but I am sticking with the D-Link / Plugable as i) I value teh speed and ii) I have noticed any data loss.
Thank you.