extremly slow wireless connection between two notebooks

[Martin Konôpka]

I am trying to transfer data between two notebooks connected using their Wi-Fi radios.

Machine 1: HP ZBook 15 configured to serve as a Wi-Fi hotspot. Network controller: Intel Corporation Centrino Advanced-N 6235 (rev 24). The machine also has a mobile broadband USB device (Huawei E3251) which connects it to the internet.

Machine 2: Fujitsu-Siemens AMILO Pro V3205. It is connected to machine 1 using wireless adapter. Network controller: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection (rev 02).

Both machines run latest development version of ubuntu 14.04. (Machine 1 a 64-bit system, machine 2 a 32-bit system.) The Wi-Fi hotspot (running on machine 1) employs the WEP authentication. The connection speed is only about 0.1 MiB/s, i.e. about 0.8 Mbps. This is far below what the Wi-Fi adapters in both machines are able to do. The particular program I used was rsync. The data were transferred from machine 2 to machine 1. The speed was the same slow for rsync invoked either on machine 1 or 2.

Yesterday I tried a different way to connect the two laptops: I created a Wi-Fi hotspot using an android smartphone with a WPA2 PSK autentication. That other wireless connection between the two laptops was at least one order of magnitude faster. (I do not remember precise number but surely it was much much faster.)

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-16-generic 3.13.0-16.36
ProcVersionSignature: Ubuntu 3.13.0-16.36-generic 3.13.5
Uname: Linux 3.13.0-16-generic x86_64
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: konopka 1643 F.... pulseaudio
 /dev/snd/controlC0: konopka 1643 F.... pulseaudio
CurrentDesktop: Unity
Date: Sat Mar 8 08:01:34 2014
HibernationDevice: RESUME=UUID=bed0cd64-3da5-43a7-b4a7-6cc72965a402
InstallationDate: Installed on 2014-01-31 (35 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140130)
MachineType: Hewlett-Packard HP ZBook 15
ProcFB:
 0 inteldrmfb
 1 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-16-generic root=UUID=56c3d081-90f2-445f-ade1-574586237cd6 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-16-generic N/A
 linux-backports-modules-3.13.0-16-generic N/A
 linux-firmware 1.126
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/25/2013
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: L70 Ver. 01.06
dmi.board.name: 1909
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 94.47
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvrL70Ver.01.06:bd10/25/2013:svnHewlett-Packard:pnHPZBook15:pvrA3009DD10303:rvnHewlett-Packard:rn1909:rvrKBCVersion94.47:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP ZBook 15
dmi.product.version: A3009DD10303
dmi.sys.vendor: Hewlett-Packard

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.14 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14-rc6-trusty/

[Martin Konôpka (martin.konopka)]

I will most likely test it soon.
However, later after the bug rerport I discovered, that ubuntu supports also creation of WPA/WPA2-secured hotspot and, surprisingly, this more secure network provides full speed, about 10 times faster than the WEP hotspot.

It is pitty that if one goes to the Control Centre and opens the network setup, it is possible to create WEP hotspot only. (At least I could not see how to create WPA from the Control Centre.) Later I noticed that clicking on the Network Manager menu provides the richer choice of hot-spot networking options, including the WPA (through the Create New Wi-FI Network option).

[Martin Konôpka (martin.konopka)]

So I added the tag (bug also in mainline). My testing concerned the default hotspot settings which are obtained using the Control Centre (not the NetworkManager popup menu). It is the "WEP 40/128-bit Key" network.
I tested two variants:

1.) latest upstream kernel (3.14.0-031400rc6) on the hotspot-generating machine AND default kernel (3.13.0-16) on the connected machine.

2.) latest upstream kernels on both machines

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

Please follow the instructions on the wiki page[0]. The first step is to email the appropriate mailing list. If no response is received, then a bug may be opened on bugzilla.kernel.org.

Once this bug is reported upstream, please add the tag: 'kernel-bug-reported-upstream'.

[0] https://wiki.ubuntu.com/Bugs/Upstream/kernel