Raspberry Pi Wired Ethernet Intermittent

Thanks centipede for the detailed facts. There are a few facts to understand:

• The ethernet is 10/100 mb/s old style technology.
• The chip that runs the ethernet also shares the bandwidth with USB. This means the FIFO stack is probable also shared(?)
• Although the Pi is getting better in some aspects like CPU/GPU/RAM, they have NOT changed the USB/ethernet chip.
• Because of the above, the Raspberry Pi is a nice to play with but not ready for heavy usage like you are seeing. Other players in the SBC arena are either better or encroaching on performance of the RPi. In my case I am using the RPi 3 only in daily operations using the WiFi constantly sending/receiving data. Except for one power outage, the system has been robust so far. I do not really tax it IMHO.

Clem 

Clem,

Thank you for your reply.

Yes, I suppose it's possible that the Raspberry PI is just not capable of sending out large amounts of data over the wired Ethernet connection, although if that were the case, I would think there would be many posts online about that limitation.  Rumors abound, and many posts online talk about using the Raspberry Pi as a web server, why has no one else already complained about this?

So I am expecting this to be some kind of configuration issue, or a driver bug.  If there is a  FIFO which fills up, then there should be a log message about that someplace.  Also, when using a ping to recover, it's interesting to see that the transfer picks up where it left off, without any apparent error other than the delay. It is also interesting that inbound files, even huge ones are transferred very very quickly and without an issue.  If this is a FIFO issue, why does not inbound traffic get affected?  If a buffer is the issue with outbound traffic, it would seem the TCP stack could be adjusted to reduce the window size, smaller chunks could be sent at a time.

One more interesting bit of information, I find that sending a ping towards the PI also 'wakes up' the wired Ethernet.

Robert

Roger, A good suggestion, thank you.

I used the original jessie file which I downloaded on 6/2/2016 and imaged it onto an 8 gig SD card.  I then booted the PI, and without any changes at all, uploaded a 3 meg file to the /home/pi directory.  Next I tried to download the same file and got this result with FileZilla:

Status:    Starting download of /home/pi/01 - Sgt. Pepper's Lonely Hearts Club Band.mp3

Status:    remote:/home/pi/01 - Sgt. Pepper's Lonely Hearts Club Band.mp3 => local:E:\raspberry pi 3\var\music\down\01 - Sgt. Pepper's Lonely Hearts Club Band.mp3

Error:    Network error: Software caused connection abort

Error:    File transfer failed after transferring 32,768 bytes in 18 seconds

Status:    Disconnected from server

So the problem occurs with the standard software and an 'out of the box' PI-3B board.

Robert

Hi centipede

     I tried to setup a similar situation with my RPi 3 since I have one too. I installed Filezilla on my intel production box running Zorin (Ubuntu like) Linux. I installed the following FTP server:

apt-get install proftpd

Here is the file I used:

I copied the highlighted file from the Zorin to the Raspberry Pi 3 and back:

I had no problems running this on a local network within the same subnet.

Here is the PI software level that is older than yours:

pi@raspberrypi:~/Downloads $ uname -a

Linux raspberrypi 4.1.18-v7+ #846 SMP Thu Feb 25 14:22:53 GMT 2016 armv7l GNU/Linux

So you can compare yours to mine and tel me the difference. I may have a different ftp server than you.

Clem

Never mind I used the wireless.

Ops!

Robert Laughlin wrote:

Next I tried to download the same file and got this result with FileZilla:

 

Filezilla is listed as an FTP client on raspbian. And such graphical clients don't stay single-protocol for long. So even if it starts out as an FTP client, it usually gains ssh support within a few release cycles. So what "server" are you using on the 'pi?

I can copy a file of 15M in a few seconds using rsync over ssh.

sent 30 bytes  received 15,673,683 bytes  4,478,203.71 bytes/sec

By using rsh instead of ssh I can increase the transfer speed up to about 8Mbytes per second without any trouble. All this is on a pi 2, I'll test the PI 3 later today for you (but I expect the same results).

Update: I now saw clem install proftpd, so I did too. proftpd increases the transferspeed of my 15Mb file to 11 Mbyte per second: almost line speed.

Not sure this makes a difference or not, but in my test, FileZilla, version 3.18.0, was running on my desktop machine, the ftp server was on the PI, and was what ever comes with the jessie file.  FileZilla was set for SFTP, using the default transfer mode.  Here is the version of jessie:

pi@raspberrypi:~ $ uname -a

Linux raspberrypi 4.4.11-v7+ #888 SMP Mon May 23 20:10:33 BST 2016 armv7l GNU/Linux

When you use "sftp" that means you're using ssh. This uses encryption of the data on the line.
that could slow things down. But still, I get 10+ Mbytes per second on my pi three. It seems that my first test with "rsync" had the most slowdown, probably in the rsync protocol (rsync was written for "slow links" so it behaves a bit suboptimal on fast links).

On my pi three that I've now tested I can transfer a 15Mbyte file in sub-two-seconds. I tried ftp, scp and rsync (both over ssh and rsh).

So your situation with transfer stopping or being slow is something specific to your situation. Have you tried another ethernet cable?

(I had a client once who declined my offer of putting cat5 in their building.... Later on they asked why things were slower at 100mbps than at 10. Turns out they had wired all the cables wrong, 10mbs communication mostly worked even with the wrongly wired cables, 100mbps had too many transmission errors so things would grind to a halt....)

Roger,

I am not concerned with the speed, I just wish the transfer did not stop after 32K.  I have tried different Ethernet cables. The cable between the pi and the switch is around 12 feet long and connects into a 10/100 switch from Netgear, which then connects to a 10/100/1000 switch shared with the desktop which is running the ftp client.  Something like this:

PI---------Netgear 10/100---------------Netgear 10/100/1000-------------Desktop

                     |                                           |       |

                     ---other machines                  |      ------other machines

                                                                 |

                                                                ----- global Internet via various switches & routers

It's good to know you had success with your PI-2 and PI-3, that gives me hope.  Are you running the same version of the PI operating system?

Is it possible we have PI's made by different manufacturers, that use a somewhat different design?

I have know problems with packets between two routers/switches not getting sent (it happens in my network and I end up resetting them!). Please try to connect the desktop temporarily to the router directly to eliminate one possible problem.

Clem

It is possible for different manufacturers but they are the same design but maybe different components. Check board and you should see the UK on the Pi.

Clem

Clem,

I connected the PI to the 10/100/1000 switch in my diagram, so both machines are on the same switch similar to what you suggested, and now my FTP transfers from the PI work perfectly every time with no errors!   I have other machines connected to the 10/100 and they seem to have no issues, so I do not know why PI does, but I am very happy to have followed your advice.  More testing to do, but this seems to have fixed my problem!  YEAH!

Thank you both,

Robert

Clem,

I connected the PI to the 10/100/1000 switch in my diagram, so both machines are on the same switch similar to what you suggested, and now my FTP transfers from the PI work perfectly every time with no errors!   I have other machines connected to the 10/100 and they seem to have no issues, so I do not know why PI does, but I am very happy to have followed your advice.  More testing to do, but this seems to have fixed my problem!  YEAH!

Thank you both,

Robert

Makes perfect sense to me. The router is buffer limited on the trip back to the switch and either "forgets" or more probably drops packets. Glad though you narrowed the problem outside the Pi.

Clem

My focus on speed is not because you would want "speed". But having proper speed means things are working correctly.

My guess is that you have SOMETHING in your setup that is flaky. Either a bad networking cable (which after switching to the other router suddenly isn't broken, i.e. a flaky contact), or maybe the exact port in the switch. I've had switches develop "bad" ports.

Clem, TCPIP was designed with "packet loss" in mind. An occasional dropped packet will NOT break a TCPIP connection. On the other hand, a continuous 10% packetloss will cause bigger transfers big problems: TCPIP thinks packets are dropped because too many packets are being sent. So it thinks that reducing the speed will improve things. A constantly overloaded link (e.g. because thousands of people are webbrowsing and the new connections that don't know to reduce speed are already overloading the link) or simply a flaky link (e.g. a percentage of packets have bad CRC and are dropped, independent of the amount of packets) will cause TCPIP big problems. But none of this would cause a connection to die after just 32kBytes of transferred data).