From: Malde <gst...@we...> - 2008-12-15 14:39:34
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Hi everyone I'm trying to bring up a mobile ad-hoc wifi net with 3 gumstix. I'm using the verdex with netwifi micro sd expansion board. the /etc/network/interfaces looks like this auto wlan0 iface wlan0 inet static adress 192.168.1.53 netmask 255.255.255.0 pre-up /sbin/iwconfig $IFACE mode ad-hoc essid GumstixNet channel 13 retry 14 txpower100mW nick GStix1 my main problem is, that the wlan0 interface mostly does not start on bootup, so I always have to try "ifup wlan0" and after this often again recieve the error Error for wireless request "Set ESSID" (8B1A): Set failed on device wlan0: Network is down. and this even happens with the first one of the three, which I try to boot. Isn't the first one who is booted supposed to initiate the ad-hoc net ? how can the network be down then ?! sure it is, but it should be raised by the one who claims it to be down ?! sry I'm kind of new to all this network stuff and this is a great deal, because in the future I want to set up the wifi net by just booting the gumstix without any other connection to them, so I would have no chance to try the ifup command over and over again ... the second big problem is ah very high latency. if I try to ping the other Gumstix, sometimes it takes about 4000 ms and more, but there are moments as well when there is just a ping rate of about 10ms and less and i have no clou on what this depends. the distance between the gumstix is about 2 oder 3 meters ... thanks for any suggestions ;) greetings Malte -- View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21014965.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Takashi <ec...@ya...> - 2008-12-15 15:56:52
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The problem is most likely to do with interference; it doesn't matter how close the gumstix are, check whether your experiments were carried out near a radio source (such as places near another access point, microwave, etc.). This could also explain the varaible latency. Unfortunately nothing much can be done about the variability because this is the nature of radio - its a shared medium. What you can try is, start up one gumstx, wait untill its ad-hoc interface is established, then power on the other gumstix sequentially. Ensure you don't power all the rest of the gumstix simultaneously. You could also wirte a shell script that checks its wireless interface: for example, while(1) { if_wireless_interface_is_down; try_bring_it_up_again; } -- View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21016356.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Matt K. <ma...@ac...> - 2008-12-15 17:28:26
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Malde, We also append a kick start to the network interface definition (the last line) in our Ad Hoc robot swarms. This seems to do the trick for "n" number of Verdex Pro controlled robots. I hope this helps. http://www.acroname.com/robotics/info/gumstix/configuration.html#e6 - Matt On Dec 15, 2008, at 7:39 AM, Malde wrote: > > Hi everyone > > I'm trying to bring up a mobile ad-hoc wifi net with 3 gumstix. I'm > using > the verdex with netwifi micro sd expansion board. > > the /etc/network/interfaces looks like this > > auto wlan0 > iface wlan0 inet static > adress 192.168.1.53 > netmask 255.255.255.0 > > pre-up /sbin/iwconfig $IFACE mode ad-hoc essid GumstixNet > channel > 13 retry 14 txpower100mW nick GStix1 > > > my main problem is, that the wlan0 interface mostly does not start on > bootup, so I always have to try "ifup wlan0" and after this often > again > recieve the error > > Error for wireless request "Set ESSID" (8B1A): > Set failed on device wlan0: Network is down. > > and this even happens with the first one of the three, which I try > to boot. > Isn't the first one who is booted supposed to initiate the ad-hoc > net ? how > can the network be down then ?! sure it is, but it should be raised > by the > one who claims it to be down ?! > sry I'm kind of new to all this network stuff > > and this is a great deal, because in the future I want to set up the > wifi > net by just booting the gumstix without any other connection to > them, so I > would have no chance to try the ifup command over and over again ... > > > the second big problem is ah very high latency. if I try to ping the > other > Gumstix, sometimes it takes about 4000 ms and more, but there are > moments as > well when there is just a ping rate of about 10ms and less and i > have no > clou on what this depends. the distance between the gumstix is about > 2 oder > 3 meters ... > > thanks for any suggestions ;) > > greetings Malte > -- > View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21014965.html > Sent from the Gumstix mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------------ > SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, > Nevada. > The future of the web can't happen without you. Join us at MIX09 to > help > pave the way to the Next Web now. Learn more and register at > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users |
From: Malde <gst...@we...> - 2008-12-17 14:22:18
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Thanks for your answers @ Takashi You might be right with the interferences, if I let the gumstix scan the available WLANs there are some others. but this is the smaller problem. I've already tried to start up one gumstix and wait with the others, but even than the interface is not brought up for sure. But the "Network is down" error even occurs when there is just one gumstix powered. I fear that I'm missing some essentiell thing -.- I will try the shell script next. Takashi wrote: > > The problem is most likely to do with interference; it doesn't matter how > close the gumstix are, check whether your experiments were carried out > near a radio source (such as places near another access point, microwave, > etc.). This could also explain the varaible latency. > > Unfortunately nothing much can be done about the variability because this > is the nature of radio - its a shared medium. > > What you can try is, start up one gumstx, wait untill its ad-hoc interface > is established, then power on the other gumstix sequentially. Ensure you > don't power all the rest of the gumstix simultaneously. You could also > wirte a shell script that checks its wireless interface: for example, > > while(1) > { if_wireless_interface_is_down; > try_bring_it_up_again; > } > @ Matt, /sbin/ifconfig $IFACE up thats the line you mean, right ? I tried it, but unfortunately I don't have the impression that this increases the rate of properly brought up interfaces during booting. Is there something else I could do to my interface definition ? by the way, I liked the hint at how to edit the hostname ;) Malde, We also append a kick start to the network interface definition (the last line) in our Ad Hoc robot swarms. This seems to do the trick for "n" number of Verdex Pro controlled robots. I hope this helps. http://www.acroname.com/robotics/info/gumstix/configuration.html#e6 - Matt </qoute> Thank you so far, Malde -- View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21054023.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Takashi <ec...@ya...> - 2008-12-17 21:50:45
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Hi Malde, There may be a few more things to check: By any chance you did not attach the external antenna to the wifistix? I had this problem before by not attaching the external antenna. If you have a wireless access point, could you bring up the wifi interface using infrastructure mode steadily? When the "Network is down" error appears, is there anything special in /var/log? -- View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21061946.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Malde <gst...@we...> - 2008-12-18 12:27:36
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Hi Takashi, the external antenna is attached to the gumstix, I checked it again when you mentioned it ;) I tried to bring the gumstix up with infrastructure net first, I used a linksys wrt54 as an access point and this worked not very stable either in the case that I defined this specific access point in the interface definition, but when I comment these lines out or just define the essid as "any" it worked fine. I'm afraid this could be due to interference as well, couldn't it ? To be honest I haven't checked the log file before, but I did so recently and I did not see anything mentioned there concerning the wlan interface ?! is there something particular that you have in mind ? Takashi wrote: > > Hi Malde, > > There may be a few more things to check: > > By any chance you did not attach the external antenna to the wifistix? I > had this problem before by not attaching the external antenna. > > If you have a wireless access point, could you bring up the wifi interface > using infrastructure mode steadily? > > When the "Network is down" error appears, is there anything special in > /var/log? > > > -- View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21071535.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Takashi <ec...@ya...> - 2008-12-18 14:38:37
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Hi Madle, It seems strange that the system is not stable even in infrastructure mode. What you can try is the following: Undo the settings you had for bringing up the wifi interface (i.e. those changes you have made in /etc/network). Setup the wireless access point in infrastructure mode, static IP address, no encryption, and 802.11b (disable 802.11b/g mix, if any). Power up the gumstix normally, log in, and bring up a wifi interface by manually executing the commands one-by-one (i.e. using ifconfig, iwconfig, route, etc.). Does that work? If so, copy the commands you have executed into a shell script, change the script to be executable. Test your script by executing it. Next, you need to tell the gumstix to execute this (wifi) script when it boots up. To do so, you could create an executable file in /etc/init.d, in which you specify that the wifi script you have just created should be executed at bootup (basically the gumstix looks into this directory for things to execute at bootup). There are a bunch of these executable files already in /etc/init.d (something like S11sshd - can't remember the names). They are used to bring up, say, sshd at bootup. Just copy one of them, and replace the link to sshd with a link to your wifi script. Make sure the new file is executable and has a unique name. Now, reboot gumstix, it should connect automatically to the access point at bootup (make sure it is not too far away from the access point!). If so, change the settings in your wifi script to bring up an ad-hoc interface instead. -- View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21074001.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: Malde <gst...@we...> - 2009-01-05 14:25:53
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Hi takashi, I tried your advice, but I even wasn't able to establish the normal static net, I've got no idea .... sry that it took me so long to answer, I needed a little time off ;) I will try again in the next few days, thank you so long ! Takashi wrote: > > Hi Madle, > > It seems strange that the system is not stable even in infrastructure > mode. What you can try is the following: > > Undo the settings you had for bringing up the wifi interface (i.e. those > changes you have made in /etc/network). > > Setup the wireless access point in infrastructure mode, static IP address, > no encryption, and 802.11b (disable 802.11b/g mix, if any). Power up the > gumstix normally, log in, and bring up a wifi interface by manually > executing the commands one-by-one (i.e. using ifconfig, iwconfig, route, > etc.). > > Does that work? If so, copy the commands you have executed into a shell > script, change the script to be executable. Test your script by executing > it. > > Next, you need to tell the gumstix to execute this (wifi) script when it > boots up. To do so, you could create an executable file in /etc/init.d, in > which you specify that the wifi script you have just created should be > executed at bootup (basically the gumstix looks into this directory for > things to execute at bootup). > > There are a bunch of these executable files already in /etc/init.d > (something like S11sshd - can't remember the names). They are used to > bring up, say, sshd at bootup. Just copy one of them, and replace the link > to sshd with a link to your wifi script. Make sure the new file is > executable and has a unique name. > > Now, reboot gumstix, it should connect automatically to the access point > at bootup (make sure it is not too far away from the access point!). If > so, change the settings in your wifi script to bring up an ad-hoc > interface instead. > > > > > > > -- View this message in context: http://www.nabble.com/Ad-hoc-Wifi-Problems-tp21014965p21291898.html Sent from the Gumstix mailing list archive at Nabble.com. |