Re: [zd1211-devs] gigafast usb dongle and shielding
On 2/5/07, Jon Smirl [EMAIL PROTECTED] wrote: The zd1211 based Gigafast USB dongles does not appear to be properly shielded. If I get my Dlink wifi link dongle too close to the Gigafast one, the Gigafast one starts receiving all kinds of spurious packets, There is no effect in the other direction. I've been playing around with this some more and I'm starting to wonder if it is software related. Under monitor mode I am receiving thousands of junk packets, I don't get these in managed mode. Is the radio programmed in exactly the same way for monitor and managed modes? One way to explain what is happening would be that the radio sensitivity is much higher under monitor mode that managed. Another explanation would be that the hardware is able to separate noise packets from good ones in managed mode and not in monitor mode. Searching around with google I see reports of people trying to use kismet with zd1211 having this same problem. Another data point, if I put a rt2500 based device in the same location in monitor mode, I don't see the junk packets. -- Jon Smirl [EMAIL PROTECTED] - Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642 ___ Zd1211-devs mailing list - http://zd1211.ath.cx/ Unsubscribe: https://lists.sourceforge.net/lists/listinfo/zd1211-devs
Re: [zd1211-devs] gigafast usb dongle and shielding
Andy Green wrote: I think in managed mode the firmware in the stick insists that valid packets are marked up with either the AP or your MAC address, or some similar strict regime. I have also seen in monitor mode nearby transmissions on different channels (!) turning up on another channel intermittently, This is normal and happens on almost all consumer 802.11 hardware (i.e. devices with inexpensive radios). It's related to both physical proximity of the monitoring device to the transmitting one, and also due to the 'resolution' of the radio and the fact that (e.g.) channel 3 is right next to channel 4 in the spectrum and the radio isn't quite good enough to distinguish between them 100% of the time. Daniel - Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642 ___ Zd1211-devs mailing list - http://zd1211.ath.cx/ Unsubscribe: https://lists.sourceforge.net/lists/listinfo/zd1211-devs
Re: [zd1211-devs] gigafast usb dongle and shielding
On 2/9/07, Daniel Drake [EMAIL PROTECTED] wrote: Andy Green wrote: I think in managed mode the firmware in the stick insists that valid packets are marked up with either the AP or your MAC address, or some similar strict regime. I have also seen in monitor mode nearby transmissions on different channels (!) turning up on another channel intermittently, This is normal and happens on almost all consumer 802.11 hardware (i.e. devices with inexpensive radios). It's related to both physical proximity of the monitoring device to the transmitting one, and also due to the 'resolution' of the radio and the fact that (e.g.) channel 3 is right next to channel 4 in the spectrum and the radio isn't quite good enough to distinguish between them 100% of the time. I'm not seeing bleed through from another channel. Instead I'm seeing streams of thousands of bogus packets mixed in with the good ones. I'm receiving the good ones mixed in with the bad ones. It is like the squelch knob is turned down too low and it is turning background noise into packets. I see the same behavior on multiple zd1211 devices so it is not a broken device. The packet data and headers just look like random numbers. Src and dst MAC address is different in every packet. If could be that these noise packets are being received in Managed mode and the firmware is eliminating them. My Ralink hardware only picks up a few bad packets in monitor mode. I'm in a fairly quiet radio environment and can't see beacons from any other nets on Channel 1. Only beacons I see that I don't control are on Channel 6. I'm monitoring on Channel 1. -- Jon Smirl [EMAIL PROTECTED] - Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642 ___ Zd1211-devs mailing list - http://zd1211.ath.cx/ Unsubscribe: https://lists.sourceforge.net/lists/listinfo/zd1211-devs
Re: [zd1211-devs] gigafast usb dongle and shielding
Jon Smirl wrote: If could be that these noise packets are being received in Managed mode and the firmware is eliminating them. Yes -- Andy Green pointed this out earlier today and he is entirely correct. This behaviour is expected. I think in this case the filtering is done in hardware, as opposed to firmware. Daniel - Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642 ___ Zd1211-devs mailing list - http://zd1211.ath.cx/ Unsubscribe: https://lists.sourceforge.net/lists/listinfo/zd1211-devs
