Mesh freeze on node shutdown

[Cristian Nasuti]

Ok!
All machine have the same PCMCIA wi-fi card (SMC 2536W-AG EU) with atheros
chipset (AR 5212).
3 machine have Ubuntu 9.04, 1 have Xubuntu 9.04.
I compiled the kernel following the instructions for ubuntu in HOWTO and
then I installed the same packages on all machines.

For all machine I use this instructions (by root):

killall NetworkManager
modprobe -r ath5k
modprobe ath5k
iwconfig
ifconfig wlan2 down
iw dev wlan2 del
dmesg | grep ath5k
iw phy phy0 interface add MP1 type mp mesh_id mymesh
iw dev MP1 set channel 9
ifconfig MP1 up
ifconfig MP1 10.0.0.1
ping -c 4 -I MP1 10.0.0.2
ping -c 4 -I MP1 10.0.0.3
ping -c 4 -I MP1 10.0.0.4
iw dev MP1 station dump
arp
iw dev MP1 mpath dump


For all machines I use the same mesh_id, the same channel (9, free, and the
most distant from other occupied) and ip in the same class, for simplicity:
MP1 -> 10.0.0.1
MP2 -> 10.0.0.2
....

Suppose that the topology that I want to achieve is this:

MP1 --- MP2 --- MP3 --- MP4

Then I try on MP1:
iw dev MP1 mpath del MAC_Address_of_MP3
iw dev MP1 mpath del MAC_Address_of_MP4

On MP2:
iw dev MP2 mpath del MAC_Address_of_MP4

On MP3:
iw dev MP3 mpath del MAC_Address_of_MP1

On MP4:
iw dev MP4 mpath del MAC_Address_of_MP1
iw dev MP4 mpath del MAC_Address_of_MP2

Then launch iperf:

on MP4, server: iperf -s -u -i 10
on MP1, client: iperf -c 10.0.0.4  -u -b 54M -t 180 -i 10

Everything works well, the throughput seems satisfactory.

Then I try to remove a node:

on MP2: ifconfig MP2 down

In few seconds the client (MP1) freeze and I am forced to reboot.
Same happens if I turn off the intermediate node MP3.


I'm not very familiar with Linux, if there is any command to get more
information about the system configuration tell me that I do and send the
results.


thanks for the help, bye!


Cristian Nasuti
_____________________________________________________________

nasuti.cristian at gmail.com [Mail, GTalk, Live Messenger]



2009/12/1 Rui Paulo <rpaulo at gmail.com>

> On 30 Nov 2009, at 18:45, Andrey Yurovsky wrote:
>
> > On Mon, Nov 30, 2009 at 10:29 AM, Cristian Nasuti
> > <nasuti.cristian at gmail.com> wrote:
> >> I think that I have the same problem.
> >>
> >> What I do is to configure 4 machine as mesh point and force paths (using
> the
> >> commands mpath mpath and new) for this topology:
> >>
> >> MP1 --- MP2 --- MP3 --- MP4
> >>
> >> Then I run iperf: suppose MP1 as client and MP2 as a server.
> >>
> >> All work fine, but if after a while I turn off one of the intermediate
> >> nodes, such as MP3 (with ifconfig MP3 down or just turning off the
> machine)
> >> after a couple of seconds client machine (MP1) freezing and needs
> rebooting.
> >
> > Thanks Cristian.  This seems to be a recent regression and we'll look in
> to it.
>
> I can't reproduce this problem. Everything works when I ifconfig down the
> intermediate node. No nodes crash and I'm able to resume the transmission if
> I ifconfig up the intermediate node.
>
> Can you both describe in more detail your setup?
>
> Thanks,
> --
> Rui Paulo
>
>
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